99 C2 Code P1531 Variocam Solenoid

So last week after leaving the car sitting over the weekend on Monday I got a check engine light within 5 minutes of driving. I checked the code, P1531, cleared it and continued on my way to work, the car was idling fine and drove fine. The code came back the following afternoon. I read a bunch of threads on the variocam solenoids and actuators to try to understand what to check. So this weekend I got some time and began diagnosing the issue. I disconnected both solenoids and tested each. Bank 2 has 13.5 ohms across it and when applying 12volts with the engine off I can hear the solenoid click. Bank 1 I get 13.2 ohms, but when 12 volts is applied no click. I then started the engine and applied 12volt to each solenoid. Bank 2 the idle changes, Bank 1 no response at all. So pretty sure the issue is the solenoid or actuator on bank 1. I do not have access to a durametric (Anyone in Edmonton with one?). I've called a local Indy and have been quoted about 1700$ to change out just the solenoid. Is there any further diagnostic that can be done to determine solenoid vs actuator?

Wait for our variocam expert Schnell Gelb to chime in. My take is your solenoid is bad if you don't hear any light click when power is applied. The actuator is activated by oil pressure so when engine is off, it would not move or make any sound. The cam cover has to come off and you can unbolt the solenoid to bench test it.

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Appears you have id'd the solenoid as at least part of the problem. With the 996 because the solenoid is (my understanding) relatively easy to get at/replace you could replace the solenoid clear the codes and road test the car. If the error comes back then the actuator is (also) the problem. Based on my 2nd hand info regarding the solenoid in the 996 engine I have a hard time accepting that $1700 quote. That seems high, about on the order of what I paid to have the solenoid replaced in my Boxster's engine, which required the camshaft cover to be removed. Before I dropped $1700 on a solenoid R&R I'd ask around/do some research to find out if that is indeed the going rate. 'course, in your location you may not have that many options.

I am a very reluctant expert. But I learned a lot from kind Forum members. My engine had a very obscure Variocam issue that forced me to test every possible issue -very time consuming but a great learning experience.One Forum member offered a test that may help a diy-er w/o Durametric - initials are J.R. He suggested to make a long test harness to connect the known ,good Bank to the suspect Bank. This test will identify/eliminate any expensive DME/wiring problems as the cause of your problem. When you redo the 12v 'click' test - be very careful. Use a test cable with a fuse, a MOM switch and the correct polarised,insulated terminals because it is easy to short the pins in the Solenoid wiring. If you do, you will melt the insulation off the wires inside the harness and may not know it.Bad, very bad. Do the click test in absolute silence and keep a finger on the top of the solenoid to feel it. The solenoid plunger operates in oil that may muffle the click. **The Durametric test is the fastest and most conclusive. Go to Actual Values . Rev to 3000 rpm. The timing should jump on the graph to 20+ for both Banks.Check your Deviation at the same time because this will give a hint of other issues that need attention(pads?) A note for Durametric uses - there have been 3 recent updates to the software.Download the latest now.Unlikely it will work well without this. In particular "Activations" may not work and you need that for further prompting/testing of the suspect Solenoid. Do not assume it is just the solenoid.It could(but less likely) be the Variocam Actuator($1000 !) The Solenoid alone is much cheaper but it is the labor !!! Be sure to get the correct side - yes, they are different !!! The Solenoid replacement can be done with the engine in the car - easier on a 996 than a Boxster . First evaluate if there are other deferred repair tasks that require engine-drop. Personally , I would not proceed until I had Durametric data to conclusively confirm the cam cover needs to come off. I am sure an Indie would agree. I can't think why you would cause any damage by continuing to drive the car gently.Yes the power/torque will be weaker on one Bank but just to go to get the Durametric test(gently) should be O.K.BTW the clone Durametric - very cheap from China&/or on Fleabay - is junk. Good luck and let us know how it goes. One issue to keep in mind re- engine drop - when preparing to replace the cam cover on the engine you must run a perfect 1mm bead of sealant all around. If this is applied clumsily,the excess drops off into the oil supply and can cause all manner of problems. Typical on bad cam cover jobs(Bank 1-cyl 1.2.3) is that you get the red oil pressure light - because a tiny piece of sealant plugs the 'feed' to the oil pressure sensor that sits on top of the cam cover .Good luck figuring that fault :-). It is much less likely that this will occur with the engine on a stand.

Thanks guys for the info. Monday I plan to talk with the Indy and see what my options really are and what actually makes up the 1700$ quick estimate they gave me. They said half labor, half parts, which seems high on the part side for just the solenoid. Must be the BC Tax(Being Canadian) ontop of the Porsche Tax. I looked up the solenoid from a Canadian Supplier (autopartsway.ca) and they want $615(cdn)$ just for a solenoid vs autoatlanta at $325(cnd). I hate to find out the cost of the actuator from a Canadian supplier... On the other hand I've only owned the car 3 months and have no records so there is probably some deferred maintenance that could be done if the engine had to come out. I know there is an RMS leak identified by the orignal PPI. I'm not suffering any AOS problems, I have Tiptronic so no Cluctch to change and with the dual row IMS I'm not itching to change it. Is there any other out of car engine maintenance items to consider?

Be careful with the parts and Part numbers. Distinguish between : 1. The Solenoid -Bank 1 or Bank 2 2. The Variocam Actuator Bank 1 or Bank 2 3. The Variocam Actuator +Solenoid as a complete unit - Bank 1 or 2. The prices will vary obviously .Use the part number, not the verbal description. Don't buy an Actuator unless they have physically inspected it. Check the little spring at the end of the plunger is still there and that the P.O. hasn't muddled the parts/Banks

We've seen this issue before. The most consistent way that we have identified it happens is that: -the solenoid for the camshaft stops working properly and it eventually fails, then; -the amperage on the wires increases and back feeds to the DME shorting out the computer The most common codes for this failure are the ones already described as P1539, P1397 & P1341. Most time the DME needs to be fixed. This is easy to tell just by the "burnt" smell coming from the unit. Then the solenoid replacement job needs to be done as well.

I had a P1341 on my car soon after purchasing. Cost me about $3000 to fix at a well-known indy here in DFW. The solenoid / actuator was $1500 just by itself. Cams and/or retainers had to be removed to replace the actuator. Some of that might be fuzzy as it's been almost 2 years ago.

While the engine may run ok as long as the failure remains intermittent it can act up at any time and who wants to live with a car that can start running poorly at any time. Thus I would not want to continue to drive the car with this problem. Also, at some point the failure will occur more often or become a hard failure and the engine can start to misfire as the DME adjusts the fueling to get the O2s sensor readings it expects but is unable to becaue of the VarioCam problem.

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That's about what I paid for a new solenoid/actuator for my Boxster. Parts cost was about $1500 (solenoid and actuator are *expensive*) and labor was the other $1500. However, to get at the solenoid the camshaft cover had to come off. With the 996 my impression is this is easier to get at and replace than it is with my Boxster thus that $1700 estimate/quote seems "high". The solenoid is I'm sure going to run around $600 to $700 (or more) but I don't think there's $1000 worth of labor to replace it.

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The Post below from ECU Doctors is important because it explains a Mode of Failure that has not been noted before. The only Resistance Test mentioned in the diy diagnostics was the 13 Ohm Test. The inference being there would be either the correct resistance or infinite resistance. No collateral damage. A much higher resistance that causes wiring harness and DME damage is alarming - and expensive. The diagnosis seems simple enough - the DME Smell TEst. But by then damage has been done ! Thanks to ECU Doctors for the alert.

I spoke to the Indy today. The price for the solenoid alone was 800$. I asked if I could source my own parts and they had no issue with that. 6 hours labor was the rest. When I get some time tonight I know I've seen a parts list somewhere. I want understand the must do stuff and what is a good idea while you're​ there. Ill try and get to the ECU and do the smell test as well.

So I just checked out the ECU, I pulled the Tiptronic module off and disconnected the main ECU connector and I could not smell anything remotely burnt or off. So I think that I'm safe there. I'm constantly amazed by the quality of parts of this car. Just the carpeted foam ECU cover fits so perfectly and is so dense its unlike anything I've seen in any previous car I've owned. Last comment, so if the solenoid has the chance to damage the ECU, and I need to drive the car to the shop, would it be a good idea to just disconnect the solenoid from the ECU before driving over?

This is the parts list I've come up. This is assuming just changing the solenoid. If just changing the solenoid would you change the 5th timing chain or the variocam pads? Solenoid Part #996-605-901-00 23x Torx Screw 6X30 Part #999-385-003-01 3 x Camshaft Seal Part #996-104-215-54

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Just separate the connector if you can? Once the cam cover is off you will be able to see if the pads need replacing.If one Bank is worn, the other will probably need replacement also. The recommended sealant for the camcover is Dreibond. Your Indy will tell you what he uses- go with that because then he is responsible for any big leaks.Make sure (without offending his knowledge) he uses the 1mm bead technique. When buying the Solenoid remember there is a big seal that in theory should be replaced but maybe if it is perfect ,a little sealant would work ? To remind you about getting the right part # for the Bank you are working on ! Try RND Euro Parts as a source? Hope this helps & good luck !

Do you mean 99610524403? it goes on the outside of the engine sealing the solenoid from the outside?

Yup, that's it.

So I decided to let an Indy handle the job and the parts. I booked it in yesterday, they hooked up the car, activated the variocam and they said everything was working as expected, Cam deviations etc were all totally normal. They held it overnight and performed the tests cold and took it for a longer test drive, the issue has not reappeared. Contrast to the week I had the issue and I couldn't drive more than 30 km without the light reappearing. The last thing I did before taking it in was disconnecting the ECU to make sure it wasn't burnt out as suggested by ECU doctors, and then I reconnected the solenoid. So maybe a wiring or connection issue, but I'm still not sure why manually activating the solenoid with the engine running didn't change the idle? The shop suggested I continue to drive it and if the light reappears to not clear it and take it in.

Odd. Bad connections - maybe. Time will tell. Let's hope it is fixed !

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If it comes back and you need parts, I have them used sitting on a shelf pulled from a 99 C2. I'll make you a great deal.

I just had this work done on my 2000 ME. Technically per Porsche manual the engine should be pulled but it's not really needed. At any rate, the $1700 quote is not unreasonable.

So its been a few weeks and over 1000 km and the issue has not returned. So either it was a loose connection that I fixed when I disconnected the sensor to troubleshoot or the shop did add oil to bring the oil to halfway on the dipstick as bar of their troubleshooting.

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So you happen to know what actual values to check for? I assume it's not ignition timing. I'm not sure I have any other timing to check (for valvetrain anyway) with ME 5.2 (I have a 99 996). I did check cam deviation, and it's the same as it was over the last 2 years (-1 and -3 per bank, respectively), and it doesn't change even when revving it (up to 3,000 RPM).

I only know 7.2. We need to distinguish ignition advance( separate issue) from deviation( a mechanical defect over a limit of around 6)and mechanical valve timing advance. I do not know those specs for 5.2.Others will hopefully chime in to help you.

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What codes are you experiencing and what are you trying to figure out? Cam deviation should be rock solid regardless of revs. I think what you're looking for is called actual cam angle, which is rev dependent.

If you think the solenoid is not working then start testing it with a 9V battery. If it works, you will hear the engine tone change when the solenoid is activated. Do the same thing to the other bank if you are not sure what to listen to. If it the engine tone changes, check if the solenoid gets +12V at 3000 rpms. If doesn't start tracing it back towards the ECU. My 996 had a blown bank 2 vario-cam solenoid transistor in the ECU. BUT it took me some investigating before I was 100% sure that was the problem. Once I opened the ECU it was clear as day that the transistor/driver was blown (you could see it was burnt). The replacement transistor was $7. Got it soldered in and it fixed the problem.

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That makes sense. Yes, actual cam angle. I have a P1530 code ( P1530 Camshaft Adjustment, Bank 1) and misfires across all 6 cylinders. I just had the plugs/coils replaced 1 hour ago and still have the same codes (not surprised). Wiring was tested as OK. Could there also be a cam position sensor issue? All roads seem to point to the cam solenoid, but then again, not sure why all 6 cylinders would show misfires.

A few possibilities that you will need to rule out systematically like Imo said. Check out his thread here . When you said wiring test out OK, how did you test it? Did you verify the solenoid gets the +12v and ground from the DME? It's possible one bank misfiring will affect the other bank. Oh and the cam sensor is likely OK as it has its own codes. Also, P1530 requires that no cam sensor errors detected.

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Thanks. Here's what a different mechanic (Midwest Performance gave me for diagnosis: "Interrogation and inspection revealed bank 1 cam adjustment fault and misfire flags for all cylinders; bank 2 oil loss, but not bank 1. Continuity tests at bank 1 solenoid ok. Advise customer internal fault at solenoid, or actuator fault tests recommended, requires removal of timing cover; measurement of cam deviation over load ranges recommended." Question: I see posts on how to replace the solenoid. Is this really a 6-7-hr job? And does it really require locking the crank/cams (as described here: http://986forum.com/forums/performan...iming-m96.html ). I was told by Midwest Performance Cars (Chicago, IL) that I was looking at a $2k-$3k deal. They said that by the time they pulled the camshaft cover off, they could discover things like - stretch chains and worn tensioner pads. And at that point, if that was the case, they might as well take the other side off and do the full pads replacement, etc. I guess I'm trying to understand if it's just a solenoid ($500 one at that, which has to make it into the top 10 most expensive solenoids of all time), or if they are trying to prepare me for much bigger issues. I understand tensioner pads, and if my car needs it, that's fine. But I don't recall these M96s having this as a common issue at 61,000 miles. Also, their labor rate is $160/hr and trying to keep my costs in check here.

"Question: I see posts on how to replace the solenoid. Is this really a 6-7-hr job? And does it really require locking the crank/cams (as described here: http://986forum.com/forums/performan...iming-m96.html ). " 6-7 hrs. Yes...It can be done with the engine in the car, but I'd recommend lowering it a bit. I've removed the cam covers both ways (engine out and engine in). Obviously it's easier with the engine out, but that'll account for way more time as it's a much bigger job - you could probably spend 6-7 hrs. just removing and re installing the engine. Yes the cams need to be locked because the cam cover forms the top halves of the cam bearings. The solenoids themselves aren't $500 (at least they weren't when I did mine) - I'm pretty sure you can get them for much less than that ($200-$300 range?). The actuators themselves are in the $1k range so hopefully those are ok... ** The other thing I experienced after replacing my cam chains and tensioner pads was that my CEL and 1341 faults didn't go away. I'd clear them with my Durametric and they'd come right back. As a last resort, I decided to remove my ECU to see if there was something going on in there (there was some talk of a chip that would either burn or de-solder itself). When I removed the ECU and opened it up, there was nothing obvious going on so I just put it back together and reinstalled it. Upon reinstalling the ECU my CEL and fault codes were gone, never to return! For whatever reason, the code seemed to be stuck in there even though I had cleared it with the Durametric. Removing the ECU essentially did a hard reset/clear of any memory that never happened by just removing the battery etc.

dporto makes a valuable and obscure point. In the many looong threads on this Variocam issues,the hard reset has very rarely been mentioned.Porschetech 3 iirc also spoke of it. The controversial aspect is - hard rset is an easy,quick,non-intrusive thing to do before you start the awful job of removing camshafts.Yes you may have to do a drive cycle. If you do remove camshafts, make sure you ask for a potential while-I-am-in-there list

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Not clear from what you wrote but make sure they did eliminate the DME, which is not uncommon. It will suck if misdiagnosed.

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My plan was to do the 9V battery trick on the solenoid with the car off. And the 3w light bulb trick. Those two should tell me, right?

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Yes the 9v battery can be used even when the engine is idling. You will hear engine note change if the variocam is activated.

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Yes, it will tell you if the solenoid is getting power when it needs to. BUT the shop should do the same too before start replacing parts that are based only on the trouble codes. A good mechanic will investigate as much as it takes to be 100% sure where the problem is and ONLY replaces that part. Regular mechanics will start throwing parts at it based on the trouble codes and the owner of the car will eat the cost. Now if the valve covers come off and the cam tensioner pads are even just slightly worn then might as well replace them since the entire mechanism will be out anyway. They parts are only $25 and labour is mere minutes. BUT I would not go and replace the other side. Your shop should prepare you for the worst case scenario but they should also explain that a proper diagnosis is necessary and that takes time. Time that you are expected to pay for. It is very difficult to get a proper estimate when there could be multiple causes to a problem.

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Thanks. One question though: when you say the mechanism is already out, do you mean just for the actuator and not the solenoid? I was thinking that the solenoid can be replaced and we won't be touching the chains or pads, since the actuator isn't removed?

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I thought the entire thing is sold as one piece but I never had to buy one so this could be wrong. If they sell the solenoid separately and the pads look good then yes, only replace the solenoid.

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Well, you are right that the whole thing is available for $1299 (996-105-051-58-OEM, left bank only, https://www.pelicanparts.com/More_In...VSVSI=0896.htm ) You can buy just the solenoid by itself for $500 (996-605-901-00-OEM left bank, 1-3). But if the actuator is bad, after replacing the solenoid, one would have to re-buy the solenoid if it didn't fix the problem. With the labor involved, this is why it's really important to figure out exactly what's not working. I can't believe how expensive this part is. I bought my 1976 Honda CB motorcycle for the same price as this one part.

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Exactly.

Since I already hijacked the OP�s thread with my own, nearly identical issue, I dipped the car off today for repair. They are reporting cam deviation �the worst they�ve ever seen� at 27 degrees. �Cannot believe it even runs,� they said. Strange, since Durametric has always reported only about 2 degrees, maybe 3 worst case. They are going to have to investigate further, but have said not to be surprised if this becomes a can of worms at 60k miles and 20 years on the it. They are going to remove & disassemble engine oil filter, replace engine filter & set oil level to spec. remove and replace cam plugs to verify camshaft timing is within spec, inspect cam solenoid for function/sticking. report results with recommendations.

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So they physically measured 27 degrees but Durametric said 2 degrees? That is am alarming discrepancy since we rely entirely on Durametric for that Actual value measurement.. There has to be an interesting explanation for that !!. Guessing some failure of the chain tensioner.Hopefully they check both banks.And such low miles.

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Do you have misfires on that bank?

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I have misfires on all 6

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They are going to need to manual check timing now instead of going off the measured values from PIWIS... For what it�s worth regarding Durametric, Al UscinskI who works for Chicago Performance and Tuning said that he never uses Durametric because he couldn�t trust it. He said this after I told him that I�ve check my cam deviations in the past and they were fine. He said he has been screwed before not using the right tools. This is the first I�ve heard the Durametric couldn�t be trusted. But if the DME is simply reporting to Durametric, how can we fault Durametric for this. I also wonder how the timing could be that far off with an interference engine and not have caused damage.

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Well that sucks with your car. Hard to believe that the Durametric can't read the deviation.....I know when I got my car, I used a generic scan tool that does many things on many cars (like a Snap On type device) and then I got the Durametric later (the first scan tool wasn't mine), and they both read essentially the same thing. I have yet to check my deviations from last year. Let us know what they find. Best of luck!

If the valves open and close early that there will be no contact between the piston and them. That’s how you can have deviation and no bent valves. Happened to a friend of mine. When he put his engine back together, he missed the cam timing on Bank 2 (intake cam) and had it off by one tooth. Took use some time to finally be 100% sure that the issue was mechanical and not something sensor related. After pulling the valve cover and checking the cam timing it was clear that he missed it by 1 tooth. His intake valves on Bank2 were opening and closing too soon. Engine was misfiring in that bank but no bent valves. After he re set it, the engine ran perfect and has been ever since (since Christmas).

Great anecdote - And the key is it was both misfiring and showing excessive deviation on Durametric on the same Bank ?

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Sounds like the little green o-ring has failed on the cam adjuster and stuck at full advance(25 degree crank).The extra 2 degrees was probably just initial setting. Schnell Gelb is an expert on this subject !!

They need more time now to test. They pulled the oil filter and did not find metal (good). There was some tiny small debris, looking like silicon sealant, some chain guide material, and some other very hard dark black plastic bits. Very small. The was one big problem, though, the bypass control valve was missing from the canister. Oh my. That must mean that oil was not being filtered, and possibly why now the actuator for the cam could be stuck. However, they are getting strange results or maybe a combination of things. They checked base timing to be good (crank to IMS, and ISM to camshafts). However, bank 1 solenoid showing 60 ohms compared to bank 2,which is 11.7 ohms. When they manually activate from the DME solenoid bank 1, from rest, there's 10V and 12.5V when activated. Bank 2 is 0V at rest and 12.5V when activated Therefore, there are testing the DME, as someone already pointed out is a common issue. The good news is that they are running a battery of tests instead of replacing parts. EDIT: They just called me to tell me that it's either a bad wire or the ECU. After they removed the DME from the equation, all solenoids and timing are in good shape. So, mechanically, I think we are in good shape.

I have my old OEM filter assembly if you want it. I am not sure if the bypass valve is in the plastic part that houses the filter or not, but I think it is.

They should have tested the wiring for the solenoids a long time ago. The proper process is that you start at the solenoid (with a 9V battery) and work your way back. That’s how I did it. Was the bypass valve in the filter housing removed? You can get a new one, comes with a filter, from your dealer for very cheap.

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I agree. I told my former mechanic (who quit and now drives a truck) exactly how to do it. Shame on me for using him I guess. But Midwest Performance Cars could have checked this, too, although I didn�t go an explain how to do it, for fear of appearing to know more than they do (that�s extremely annoying when a customer comes off as an expert). However, they only did a 1-hr initial test, so the 2nd time round, they are spending more time doing it properly. Maybe they won�t charge me for all the hours they consumed because they could have tested easier/quicker, we will see. As for the bypass in the filter, they already reinstalled the filter and included the bypass valve.

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Going back to this, you did not check the cam deviations after you had the check engine light, so you don't know if Durametric has ever read them wrong before, especially based on Porschetech's post about the 24 degrees + the 2 previous degrees recorded. Just curious to see if this is correct, and if so, the Durametric most likely is reading correctly.

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I actually did, thanks to you letting me borrow the Durametric. So yeah, Durametric appears to have read the correct values.

So the most recent update from Chis and MPC is this: - the mechanical base timing is correct- the resistance of each solenoid, spec = 13.6 ohm. Bank 1 = 15.4 ohm, B2 = 11.7 ohm- checking voltage with the solenoids connected and manually activating through the DME, B1 = 10.4v then up to 12.46 when activated. B2 = 0V then 12.46V when activatedWe believed the B1 solenoid was shorting in the wiring or at the DME, or the DME was attempting to activate the solenoid to compensate for an issue between the B1 exhaust and intake came.- measuring resistance, we found no short to ground in the wire from the DME to the B1 cam solenoid- with the solenoid disconnected, the engine seems to run a bit better- when manually jumping the solenoid, the solenoid activates correctly- with the timing okay & solenoid activating, we're pointing at the DME which is likely shorted internally causing the B1 cam solenoid to stay activated with 10.5V. 996 DMEs are no longer available new, only remanufactured by Porsche. Given the time and cost, we're looking at options to have your DME removed and sent out to be rebuilt. The risk is if the re-builder blows out any pertinent information or VIN specific information.We'll likely have some options and pricing for you tomorrow.

ECU Doctors in Florida may be a useful resource??

Yeah, I may give them a try.

So my bill to investigate all this stuff came to about 7 hrs of labor. Does that seem too high or normal? The DME for my cab has to have the service position access and all that tracing of wires and cam timing stuff took a lot of time they said.

I can't say it sounds unreasonable. If it took 3 hours I would say you are the luckiest person in the world. I know when I am troubleshooting something, it takes a lot longer than you think.

Mike: Did you ever resolve the issue? Let us know!

I think the DME will come back from the re-builder and it will make no difference what so ever. The shop is rushing into conclusions without making 100% sure the problem is the DME. Chasing electrical problems is difficult if the person doing it is not systematic. When I did mine, took me several evenings to come to a 100% conclusion that the issue was with the transistor/driver in the DME. Doesn't matter how long it takes, the mechanic should be 100% confident that they know exactly what the issue is before ordering ANY parts. BUT for this the car owner has to understand that the mechanic's time will cost money to do all the investigative work.

Funny you should ask. I just heard back from EDU doctors, and I am not at all surprised that they found no issue with the ECU. Here are their notes: "The unit tested good, and it worked on our bench. Also tested the unit in a perfectly running car and found no problems. The problem might be located in the car. "Check or replace CAM solenoid valve, Check grounds, Check wiring harness, Possible engine mechanical problem, timing chain issue or wiring harness issue. We recommend these improvements to your vehicle setup: Electric Connector Harness Cleaning Kit (more info)"

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Yep - I'm $1500 in labor into this, and haven't gotten anywhere. So I agree with time spent, but how do we know the quality of the time spent is worth every penny? Hopefully I can talk to the shop again and not have to spend more money for faulty diagnosis...

Does anyone have any ideas? I just received my ECU back from ECU doctors and it tested good. They even put the DME in a vehicle (not just bench test) and it was good as well. In looking at how Variocam works, I assume that below 1,300 RPM and above 5,920 RPM, the solenoid should be OFF, correct? In the range between 1300-5920, the solenoid would be ON, which would advance cam timing by 12.5 degrees (25 crank degrees) to better charge the intake. But outside of this range What would cause the ECU to think that it needed to activate the solenoid, even at engine speeds where it should be off? I've looked at the mk1 and mk2 service and workshop manuals, but I don't see where this is all explained or discussed https://rennlist.com/forums/996-foru...-a-primer.html

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Since it has already been established that bank 1 has 10.5v not activated, and bank 2 has 0.0v not activated, seems the logical thing to do is to swap the pins at the DME from bank 1 to bank 2 and visqa versa. If the 10.5v moves to bank 2, the DME is at fault, if it stays on bank 1 the bank 1 solenoid/wiring is at fault. When to activate the vario-cam is strictly rpm related, except when oil temp is extremely high, then is delayed a couple hundred rpms.

The plot thickens. MPC is pretty insistent that the ECU is faulty, so they've asked to call ECU doctors to determine exactly what tests were done on my ECU to understand this better. If I wanted to swap the pins at the DME myself from bank 1 to bank 2, is that easy to do? MPC said that for them to do it 'would cost more money, and don't be surprised if the results point to the DME.' Not sure how much is more money at this point. As a reminder, MPC's findings: - X59/1 pin 14 negative to chassis ground OFL - DME pin 52 chassis ground OFL - DME pin 52 to pin 2 on solenoid .3 ohm (ok) - no short to ground in wire from DME to bank 1 cam solenoid - DME is shorted internally causing bank 1 solenoid to be "always on" energized 10.5V - with solenoid disconnected, vehicle runs noticeably better - can jump solenoid, solenoid activates correctly - engine mechanical timing confirmed within spec

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So I had them do this, and here�s what they found: � the culprit is an internal short in bank 1 cam solenoid� They want $2600 to fix it. This is after the $1500 I already spent on the other work that led up to this. How did they not find this short a long time ago?

" They want $2600 to fix it. This is after the $1500 I already spent on the other work that led up to this. How did they not find this short a long time ago?" Hmmm, and they were insiting that it was the DME/ECU ? How do they explain that position? Listen, everyone makes mistakes - but they should also own up to them. They should work with you on that $ number. It's not that big a job to replace the solenoid. I think a new solenoid is around $500 - but can be gotten cheaper as well. $2100 sounds like an awful lot for labor... Good luck

Quotes source post: 15933689

If you search on Renntech you'll find details of a simple functional test for the variocam solenoids..It is the click test performed with the engine off.. 1. Listen for a 'click' when you use a 9v battery to apply voltage directly to the solenoid. 2. Or. rig simple MoM switch+small jumper leads+3A fuse to a 12v car battery and do the same. In the case described in this thread a click/no click symptom would have produced the correct diagnosis for a trivial cost and at most 20 minutes of simple work.. Durametric can do the same thing.. These solenoids are probably the most expensive 12v switches in the world ! But the diagnosis is cheap and simple. Just because the solenoids both click does not mean you won't get a solenoid malfunction code. Indeed, if the DME is faulty ,tht could be the cause. But at least the click test helps narrow down the possibilities. There is a significant amount of labor/skill in replacing a solenoid if you are to avoid oil leaks afterwards. Patience, meticulous prep and the correct sealant help. Ahsai has a few posts showing some details. Please check that the external wiring of the solenoid is not shorting before you buy a replacement. Ask here for suggestions on the lowest price for a replacement solenoid. Someone may have a good used one. Be very careful in the replacement process not to loose a spring.See Renntech for more.details. Good Luck and I hope these comments help you.It is amazing how the engine 'sings' when both cams are in harmony:-).

Quotes source post: 15933897

They are working with me on this.

How many hours do they claim they need to swap out the solenoid? What happens if it doesn't fix the problem? Are they going to go back in and put the old one back and don't charge you for any of that work? I'll be perfectly honest, I lost confidence in this shop several posts ago. I don't know you haven't

Quotes source post: 15934893

Not sure how many hours, originally it was 7-9 hours. If it doesn�t fix the problem, that�s a good point. I don�t know, other than I would pay them after the work was done, not before, so I would have leverage at that point. Where I�m at now is: I thought about doing the solenoid myself, at a cost of $700-$800 for parts. I cannot find the solenoid much cheaper than $500. There are other parts needed, such as o-rings, gaskets, spark plug tubes, fasteners, etc, maybe special tools. I�ve been without a car for 3 months, so doing it myself would cost me another week or two. I�ve paid them $1250 or so already, and they asked for another $1500, but I�m countering for $1150 more. So if I could do the job for $700-$800, another $300-$400 for them to do it is worth it. Unless they screw it up, lol. That said, I think they are competent - the engineer seems good. They claim to warranty their labor and parts for 3 years, so if it doesn�t fix the problem, can I put a warranty claim on it, lol? I think I just did that on my labor.

Pelican has a good diy for this job. Doing the solenoid doesn't seem too bad. I just picked up a '99 throwing the same code, but this car has been diagnosed as having a bad actuator/tensioner which is a lot more work and more costly. My car has a bit of a rattle on startup and I'm told the actuator is bleeding down when the car is off, so the dme sees the cam timing off on startup very shortly until oil pressure builds back up.

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You are 100% that is what is happening or are you making a guess?

Quotes source post: 15935384

No, no! Make sure it is crystal clear with the mechanic what happens if the part and labour doesn't fix the problem. You will not have the leverage at that point but the shop will since they have the car and can easily slap a mechanic's lean on it if things go sideways.

Quotes source post: 15936827

The actuator was diagnosed by two local Porsche shops. The explanation of what's happening came from the first. No, I am not 100% sure if an internal component of the engine is bleeding down oil pressure when it sits.

Quotes source post: 15935426

My car also rattles/knocks on cold start. A lot of 99s do that. I can almost eliminate the noise if I drive off immediately. The longer you wait after start, the longer it takes for heat and oil pressure to build up. The tensioner are at the end of the oil circuit, so it will take time to get the pressure at the tensioner. I�ll let you know if my tensioner pads are a problem for my code (P1530), but I�m expecting pads that look OK.

In theory leaking lifters may also contribute some noise.

Quotes source post: 15933689

Glad my suggestion accurately confirmed what the culprit is. Hope you can now get it resolved for a reasonable amount of $$$ ... PS:Edit: Why would anyone assume that this will not fix the problem??? The 10v residual voltage moved to the other bank after swapping the pins at the DME, and the wiring was already confirmed/tested. Unless you have absolutely no faith in their troubleshooting/testing ability, this should be case closed (except for the actual repair)..

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They are not going to give me an answer to a question like this, other than �it depends on why� the solenoid didn�t fix it. Their approach all along on this is to pay by the hour for services rendered. They are eating 8 hours already. If this doesn�t fix the issue, then they have 2 misdiagnoses, or else it�s the pads or tensioner itself. None of these results is terribly bad. I would have to pay for the tensioner or pads. They would have to eat a 2nd misdiagnosis. I get what you are saying, but if it comes to things being held hostage, that�s not good for anyone, but especially not good for them. I have documented this whole process and they are being reasonable.

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^^ That's fair on their part - good luck, I hope it works out for you. You must be dying to drive your car...

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I appreciate it - thanks. I agree this should resolve it, but sometimes basket case situations just get worse and worse and worse. My car is pretty clean, though, so a I don�t expect surprises, even though they do. They said, you�d be surprised what we find once we open it up. They even suggested the exhaust bolts will likely break when they take the header off. While this is true, I have a suspicion mine won�t. The car just doesn�t have rust or any other issues. We shall see.

Quotes source post: 15937141

I really do wish you good luck as seems that you have anything but, with this car.....for now. There is a systematic way to diagnose something like this and if the proper steps are not followed or if they start jumping around and guessing then things like this happen. Doesn't help when the customer starts calling the shots either, I know you meant well but this can confuse even the best mechanics. This is an electrical circuit issue so someone that is really good with circuits should be looking at this using an accurate wiring diagram and and a very good understanding how to check them.

Just letting everyone know that my car is fixed. The P1530 code, after all, was a bad solenoid on the bank 1 actuator. The mechanic said that the tensioner pads looked good, too. The exhaust bolts all came out fine without breaking - what I consider to be a testament to the previous 18 years of garage queen ownership. No rain, no salt, no winter, driving. They didn�t think much about the cold start rattle and said that a lot of these cars do that. The engine purrs like a kitten smoothly now and seems to have full power as before.

Mike- That is awesome to hear! Too bad it took so long and $$$$. What's this no winter driving? I see you driving around all the time!

Quotes source post: 15945384

Excellent !! Glad you got it fixed and posted the conclusion, so many threads are left hanging it's good to see some conclusions.. !!

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Yeah, I kinda feel bad for the people who owned the car and �saved it� by not driving it in the winter, only for me to say forget that noise - I�m driving it in all weather conditions! Then again, it�s a 911, it�s meant to be driven

I'm glad they finally found what they were supposed to find on the first day of diagnosis. Did they leave the old pads in?

Quotes source post: 15947032

Yes, they left the tensioner pads alone. I would not have wanted to spend the money on preventative replacement anyway. To be honest, I know some 911s need to have the tensioner pads replaced on different models over the years, but to me, this is an unacceptable design problem that no engine should have. So I�m glad to hear that mine was just fine. I didn�t ask them to look at the other side or the pads further down into the engine.

Quotes source post: 15947291

Every engine ever made with chain pads sooner or later will have a problem as they are a wear item.The way the pads exert pressure, one wears faster than the other so just because the top one looks good doesn't mean the bottom one does too. I can't remember if the top or the bottom wears faster in your case but next time, have a look at both.

Quotes source post: 15947400

Maybe they are a wear item, I just don�t think they should be. Maybe Porsche should sell a pre-oiler as an option to reduce startup wear on these engines? Perhaps the design choice to get rid of the IMS completely in the 9A1 helped solved this problem. The problem is, I believe one has to split the case to have a good look at the other chain ramp pads. So it�s a lot of work to go and take the whole engine apart to service a wear item. That just doesn�t seem right to me. What if the pads and chain ramps are fine after doing this work? Maybe if someone is going to rebuild the engine, of course. Kinda like reusing old bearing that�s are in good shape, it makes sense to replace those items, but not proactively unless there�s a known defect.

The IMS has noting to do with the vario cam tensioner pads. This tensioner has 2 pads, one wears faster than the other. So, when the valve cover is off, it's a good idea to look at both and not just assume that since one looks good then the other must be ok too. Also, lack of lubrication is not a known problem on these engines so "pre oilers" are not needed. I don't know any car engine manufacturer that does this.

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I see what you mean - there are 2 pads on each bank by the tensioner. And you are talking at all about the other pads that serve the chain guides. I wonder if they looked at the bottom pad. I will have to ask them.

Quotes source post: 15945384

Thanks for the follow up!!

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No problem - car is still good, problem hasn�t returned. Now I need to figure out where the convertible top hydraulic fluid is disappearing off to. I sense a pair of actuators being a part of my future

Quotes source post: 15945384

How much was the bill?

Quotes source post: 16208717

$3000.

I had a 1531...turns out it wss the tensioner sticking after varioccam kicked in. While the RPMS returned to idle, the tensioner and it's functions were sticking. Mine only stuck when it got fully warmed up btw. A new tensioner kit, and she's good as new.

I've been reading up on this topic. I hate how complex and labor intensive it is to get at the solenoid. Add to that the fact that the engine in a Porsche is basically hidden, and you have a frustrated shade tree mechanic! (Can you tell this is my first Porsche? &#128559 I have a QuickJack, so that helps, but man, these things are not DIY friendly! The good news is I have a very trustworthy Indy. The bad news is he ain't cheap. Sorry, rant off.

Since you have some sort of a lift, this isn't that hard to do. All of this is accessible from below. If you need a bit more room just loosen the rear engine mounts and drop the engine a couple of inches. Save you hard earned money and do the work yourself. There is a lot more satisfaction doing it yourself then just forking out the money for a shop.

Question: if one of the solenoids is bad, is there any benefit to doing the other side solenoid at the same time, preventatively? Some of the labor would need to be duplicated, like dropping the motor, but not all of it obviously. For anyone who has had a solenoid fail, did the other one eventually also fail?

Quotes source post: 16068801

In my case, it eventually started to appear in front of the rear wheels....hydraulic cylinders started leaking. Relatively easy DIY to replace them with rebuilt ones

Quotes source post: 16218325

Maybe, it depends on if the mechanic gives a deal on labor for both. But not likely. For starters, the solenoid is a $500 part on the VarioCam (early 99 cars and up to 01). Mine took 20 years to fail, so will the other fail any day now or run another 10-20 years? Most parts on these cars will NEVER fail. The early VarioCam needs the valve covers removed to change the solenoid, which involves taking off the exhaust headers. So just one side is 5-7 hours of labor. The later VarioCam Plus engines have solenoids that can be removed without having to take off the valve covers. That part might be cheaper and easier to replace, which begs the question: if it�s so easy to replace, should I go ahead and wait until it fails because it�s so easy, or should I go ahead and replace it anyway because it�s so easy. My advice is to trust that most of the parts will just not fail, and we can go broke proactively replacing things that don�t fail, while other parts that weren�t included in the scope, fail. If I were rebuilding any components of the engine, though, such as tensioner/pads, that�s when a I would go ahead and service and replace those items, including the solenoids.

Thanks. Yea, $500 for a solenoid - sheesh! And I did read up on the job. The cam cover is really, well, a misnomer. It's more like the head is just split in half, so it's a big job to get to it, take it off without screwing things up like having cams pop out onto the floor (i hear they don't like that), etc. LOL Next week my Indy will evaluate. Maybe he'll get lucky and find a short somewhere, since the car runs and idles perfectly. And my mechanic is honest, so there is that.

Two questions: 1) of the folks who did one bank, did the other bank ever go out on them later? 2) How often was the tensioner assembly the problem or was it usually just the servo?

Quotes source post: 16229282

My guesses based on extremely limited data points: 1) - not often 2) - half the time

I wouldn't worry about the other side until it is a problem but I would change the tensioner pads.

I'm having the full assembly replaced on bank 1. The car runs well despite the CEL code, but he determined that sometimes the tensioner is not working. The solenoid appears to be working most, if not all the time, or at least trying to work and the thinking is that the tensioner assembly is the problem. So, since it costs so damned much to get inside the cam cover on these engines, I don't want to take a chance by replacing only some of the parts. I try to keep this car very well maintained. I will hold off on doing the other side since it appears to be fine, and I couldn't find anyone on line who had both fail (ie, fixed one, and then a week later the other failed, that sort of thing). Anyway, my Indy is a very well respected shop. Lead tech was supposedly the #1 factory tech some years ago. All I know is that they are honest and trustworthy, and that they also build and service race cars, many of which are 911's, but not all. They know what they are doing. Oh, and the tech said when he was at the dealerships years ago, they always replaced both sides at the same time even if only one side was failing, but that was likely when it was covered by warranty!

Just an update on this: I picked up the car this weekend. The job was 14 hours of labor!!! He was able to do the work with the engine in the car but they did drop it a few inches, removed the rear bumper and the muffler for access. The car is runny REALLY well, seems faster, if that's possible. Might just be the cool weather or that the car missed me driving it for these 2 weeks. :-) I REALLY hope the other side lasts a long time because 14 hours of labor is a lot of time... AND MONEY! NY rates ~ $130/hr. ouch. My indy showed me all the factory specialty tools he had to use from his engine rebuild kit. This is not a job for a shade-tree mechanic IMO. Naturally, keeping the timing right when doing this job is critical. I HATE that I cannot do as much as I would normally do on my cars. I've had my Pontiac engines down to the short block before - heads, cams, etc. But without decent access to things and not having a real lift (I have a QuickJack only), it just sucks. Who the hell designed this thing with 5 timing chains! sheesh. Anyway, hopefully I'm good for a while. I do enjoy the car.

Quotes source post: 16276942

I know, such a �simple� solenoid is not so simple to replace. Like a simple heart valve . People often complain about the high cost for these cars, such as a $15-$25k engine rebuild. But I was just quoted $10k for a new convertible top by a Porsche dealer. That included $5700 for the new top. I think your other side will be fine for awhile, I wouldn�t even think about it. We�ll likely have many other costly repairs coming later that won�t have much to do with a solenoid . It�s certainly possible your car is faster now that it�s running perfectly. A bad solenoid, despite the error codes and misfires, still cannot allow the engine to move the proper amount of air at certain given RPMs for that bank of cylinders. A solenoid stuck open/activated will have limited power between 1300-5120 RPM. A solenoid stuck closed might have a rough idle and limited power above 5120RPM. I�m not sure how you were driving your car with the error codes, but the engine makes the most power between 5120-6800RPM.

I had a car that threw a code on bank 1 and I took the engine out for a bunch of other things. While we were at it, I changed both assemblies for both sides because access is so much better. The dealer from whom I bought the parts made a mistake and sold me two identical assemblies (they are different one side to the other) and the car went back together but did not run right. So I had to do the job over with the engine in the car. Fourteen hours is a fair number if done with engin in. With some experience, a good tech can do it in one day. The dealer hourly rate in this area is $240 / hr. So your $140 is a good deal. There are a $500 worth of tools for this job.

The car was running perfectly fine, really good actually. Then the CEL came on. It was still running fine. I read the codes, cleared them and went for a ride. It drove the same, which was fine, but after about an hour, the CEL came back on. That's when I made the appt with my Indy. I always run the car through the entire tach ("I paid for the entire tach, I'm gonna use the entire tach!" lol ). I don't beat on it all the time, but I do run it both mellow and I like to wind out a few gears getting onto the highway (hell, that's why I drive these types of cars!). The indy said at first when they checked it, the vario was working ok, then it was sort of sticking. so I guess for the last 2 years or so, it's possible it wasn't running 100%, but it NEVER had a rough idle. Anyway, I just worry about the other bank's chain guides since this bank was pretty worn at only 39k miles. It's just that it's a lot of money to get in there as a preventive item. On the other hand, the engine IS MUCH quieter now, especially at startup. And it wasn't bad before! The lead tech at my indy's shop who works on my car said the motor sounds good. He said to just keep an ear on it and bring it back if I notice more chain noise starting. (He was a former Porsche tech who was supposedly like the #1 guy in the country years ago - like when these cars were still under warranty :-) He's done several of the vario tensioners under warranty. He said he always did them in pairs, but then again, the cost was covered by warranty! Hopefully I'm good for a while. I don't like dropping big dollars out of the blue without at least doing upgrades. I mean, spending $3+k on a muscle car buys a lot of added HP.

This job is totally doable by someone like you that have engine wrenching experience. The cam/timing locking tools can be bought online for not a lot of money and when the work is done, you can sell them to recuperate some of the cost. You already have a lift so don't be afraid to tackle it. This engine is not that much different than most modern DOHC variable timing engines. The only unique thing is the cam caps are cast into the valve cover. Otherwise they are the same. 14hrs is a lot of time for a pro that did this many times to take but what can you do. Get the locking tools and swap out the tensioner solenoid pads over the winter and you will feel better about it. The pads are only $40/pair.

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Holy Molly !.......I got mine replaced for 1500.00 (all in).....obviously, not at the dealer, I purchased mine from an online vendor and had someone install it......

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Im with you, I�m going aftermarket and a local shop that has very high ratings for about $2k.

Quotes source post: 16277038

My tensioner pads looked OK at 62,000 miles, and I keep track of my cam deviations, which are about -2 away from each other (+/-6 is the limit)

What tool do you need to track cam deviations? I have a pretty decent OBDII reader (it reads SRS/airbag and stuff). I forget brand right now. It reads lots of stuff that I don't know what they mean ;-)

Quotes source post: 16279581

Durametric is what I�ve used, consumer edition.

What do you think of this wear? (the guide on the bottom is not worn at all)

Compared to what mine looked like, this is bare broken in. Check out the pictures in post # 70 https://rennlist.com/forums/rennlist...f-these-5.html

I read your thread. You are a brave man, digging in like that on your first time with these motors. Very cool though, to pick up a project like that and tear it apart. That's the best way to learn. Yea, my pads are obviously no where like yours were. What does normal wear look like on chain guides? (Remember, old school American V8's don't need no stinkin chain guides! And only had ONE timing chain too. A novel idea.) I heard the Audi V8's have one giant chain, and it's sandwiched between the engine and tranny. Book calls for 40 years of labor to replace! ouch! So much for that used S4 lol

Would this material that the chain guides are made of, would that show up in an oil analysis? And if so, as what?

You don't need an oil analysis to see chain guide material. You'll see bits of brown plastic (that used to be white/off white - this id cam chain guide material) in your oil sump if you drop the plate. You may also see black plastic - this is the main IMS chain guide material.

I was only asking since I do the UOA anyway. So I was just curious.

When replacing the pads, be aware that there's a "top" and "bottom". One will contain a small hole for oil. On one bank, the oil is provided from the "bottom", on the other bank, the "top". I missed this when doing my rebuild (on bank 1 I believe), but my subconscious kicked in when sleeping one night and was able to go back and fix it before performing the timing.

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I never paid attention to this. Oh well, we'll see how it hold up. Been in the car for 12K kms so far an no wear other than staining from the oil.

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I think i just jinx'd myself. I was driving the other day and did an aggressive slowdown/stop from highway speeds and then smelled something burning. At first, I thought it could have been brakes, but then it smelled like wiring and still smelled pretty bad, even after trying to clear the smell by rolling down the windows.. Now I have P1539 code Camshaft Adjustment, Bank 2, Actuator triggered, no active position. Potential causes: - Open circuit in triggering wire. - Open circuit in B+ supply. - Actuator faulty.

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I have seen that before, car was blowing the fuse for "engine electronics" in the fuse panel and would quit running, after replacing the fuse I could smell wiring burning. Turned out the vario-cam solenoid was shorting at times. I think the wire gauge for that circuit is a little too small, or the circuit protection (fuse rating) is a little too high..

Quotes source post: 16288450

The smell associated with mine was due to the engine running poorly after my tensioners were sticking. This was throwing the variocam for a loop and sending a fault code. I had both tensioners redone(only one was sticking when the motor warmed up) and it has run flawlessly and the idle is soo smooth now.

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When I bought my car as a non runner and then got it running, one back had a faulty variocam code. The problem turned out to be a fried transistor/driver in the ECU. You could see the burnt up part on the circuit board but I don't know if that smelt bad or not since it happens before I got the car. If yo smelt the burning inside the car, pop open the ECU box.

Hope it's nothing too difficult Mike.....if you need any tools or the Durametric, you know where I am.

Quotes source post: 16288611

Yep, that�s exactly what that burning smell was. Two pics, one of each side of the opened up ECU. One looks clean, the other side has a smoking gun. So what did you do to ensure the wiring isn�t the problem? If I have the ECU repaired, will I burn it up again when reconnect everything? Clean side Burned side Remember, this all happened when I stepped on the brake pretty hard, so I wonder if that�s part of what may have triggered this. Perhaps water or a fluid was involved, although I don�t see any water/fluid on the DME itself.

The transistor can be replaced. Somewhere in Search you'll find a part number/source that I and others posted.

Quotes source post: 16319540

I think this is the thread you are talking about : https://rennlist.com/forums/boxster-...cu-repair.html I�m taking my car in to the mechanic so they can test the wiring and actuator before I start on the ECU repair. Does anyone think the hard braking contributed to this issue? The burning smell happened immediately after a hard braking event. The question is: how?

Quotes source post: 16319347

I'll get your the part number in the next day or so that I used to replace mine, Checking the wiring is easy. Just check for continuity at the pins that go to the vario cam solenoid. The way I check the solenoid was to run a 9V battery and see if it worked when the engine is running. That's all I did before finding the same thing in the DME as you. They went online to look for the transistor but no info was available for the 996 so I looked at other forums. I think I found the transistor info on a Mitsubishi forum. Bought one for $10 and installed it using regular solder tools and methods. It has been working flawlessly after the swap. You can do all this yourself and save a lot of money too.

Mike, if the soldering task is beyond your skill/tools - it should be possible to take the old board and new part to an electronics repair place and get them to carefully desolder and repair.. You'll need to search locally for a hole-in-the-wall type place on the wrong side of the tracks ? Maybe someone knows of a small business that would do this by mail ? The problem would be testing the board. It is easy to R&R so just reinstall and drive it? ECU Doctors would repair/replace and verify all the other functions but would be more expensive.

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For sure. There are a couple of places that work on audiophile electronics gear around here... But the car will have to sit at the mechanic shop while I drive back and forth (it's 1 hr away), as my mechanic doesn't recommend I drive the car with the ECU in the current state. So while I could probably save $500, which is a lot of money, it's about 10% of the total cost of the repairs I need to make after driving 4 hours total (using my wife's car). The mechanic also found worn chain guides (top and bottom of the actuator on bank 2), so I authorized them to repair that too. Finally, the convertible top needs a replacement, along with 2 new hydraulic rams, so the total cost for all this work will approach $6k. My mechanic is willing to send the ECU to ECU doctors, which saves me quite a bit of trouble and time.

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This repair and the diagnosis should be a sticky, I have a feeling as these age more this failure will become more common. The price of a NEW DME for the 99 is now close to $ eight thousand dollars !!! Not that very many will buy a new DME, but the cost of a used one and the labor to diagnose this issue can still add up quickly... Nice work Imo, I remember when you first found this issue, you deserve a good "pat on the back" for coming up with a $10 fix for an issue of this magnitude.. Where is our Mod? Can we get a sticky here?

I kept the little bag that the new replacement transistor came in but I don't think I have the invoice anymore. But I'm pretty sure this was the kit and it came from here. https://www.diyautotune.com/product/...river-mod-kit/ I didn't use the resistor from the kit just the transistor and the mica (plastic) insulator that went under it. Essentially I just replaced what was fried in the DME. The following where on the small pink bag the kit was in: MK-BIP373 PCBv2.2 & PCBv3 ModKit (1) 330o 5% Res (330QBK-ND) (1) BIP373 (1) Mica

Quotes source post: 16229282

So I have both P1530 and P1531 code showing recently on the 1999 C2. Sounds like a potential candidate for repair on both banks. The codes starting showing up at the same time. Wondering if that indicates anything in the diagnosis? My car has about 10,000 miles of track driving on it and it still has good power. The codes start showing up on the track after the engine is warmed up and after the track session the idle is rough. I've had to have the ECU rebuilt before due to misfires caused by deteriorated soldering. Track driving seems to create more vibration than Porsche planned for with their ECU design.

Quotes source post: 16987787

Make sure you test the heck out of this to be 100% sure what the problem is.

Hi, I have similar symptoms on a 99 with 56k. There's a bit of a chain rattle at start up. Can you advise with the shortest possible steps and the approximate cost?

Quotes source post: 17035844

Assuming no need to repace the solenoids or tensioners, and all you need to do are tensioner pads, top and bottom, both sides, I�d bet you are looking at 7-12 hours of labor. The pads, gasket/sealer, new valve cover screws, screws for the scavenging pumps, spark plug tubes (are prone to breaking), and sometimes broken exhaust bolts that need to be drilled out if rusted (mine were not) are all going to cost $100-$200, plus oil service. So it could be $3-$5k (Chicagoland pricing). However, you might find the opportunity to discover �while your�re in there� work. A tensioner assembly, if failed, is like $1300, but that comes with a new solenoid. You might also have the spark plugs replaced whiles you�re in there. And you might also do a bore scoring check since the mechanic will have access to all holes from the top, and would only have to drop the sump plate from the bottom. And then inspection of the coil packs.

The last warm day we had I got mine hooked up to the durametric. Cam Timing at idle: Bank 1= 0 Bank 2 =0, at 2000 RPM Bank 1=0 Bank 2=9 The car runs fine, no misfire, no hesitation, no rough idle. Only the Code P1531. My workshop is my driveway so if it's wet or cold, there's no work being done. I have yet to remove the engine cover until warmer/dryer weather arrives. Wondering if the Solenoid and actuator are fine but it's a wiring issue or Cam Position Sensor Issue. I do know Cam Position Sensors can get covered in metal filings or if not seated properly or hooked up properly can send erroneous signals. A $100 CPS is a lot cheaper and easier to replace than a $500 Solenoid or $1,500 actuator assembly. The DME is NEW from ECU Doctors. It was reprogrammed and cloned due to an Immobilizer issue over the winter. Thoughts please.

^^ Pretty sure the P1531 is specifically calling that the cam position sensor is working, otherwise you�d get a different code. See post #28. It�s probably the solenoid. Those solenoids fail way too often in my book. However, you are correct to properly troubleshoot. Make absolutely certain the wiring is not the problem (the wiring is often NOT the problem. The wiring on this car only seems to fail when an animal chews through it. If you have an early 5-chain motor (3.4), you probably want to plan on replacing both top and bottom tensioner pads while you�re in there.