Failed Smog, SAI Monitor Not Ready

It's been awhile since I've been on the forum! I think my IMS DIY was my last post. It's been a whirlwind couple years. I finished my dream workshop complete with a lift, then promptly left San Diego and moved to Los Angeles a few months later when Disney found my resume and called to offer me my dream job as a Disney Imagineer with Walt Disney Imagineering Research and Development (I'm an electrical engineer and physicist). Too bad I hate LA and don't have a garage/shop anymore. But Disney is awesome designing the latest rides, animatronics, and technology for the parks and resorts worldwide is pretty freaking fun. Ok, on to the post. I failed smog today, with the note: "OBDII Monitor Not Ready: Secondary Air System". In CA, you're only allowed to fail one monitor on cars newer than 2000, and it can only be the evap emissions monitor, no other monitors. My car is a 2001 C4, manual. In the last two months I've: replaced the spark plugs, all coil packs, the AOS, water pump, thermostat, oil filler tube, and window regulator. The battery was disconnected for most of those, so all the computer's monitors would need time to gather data to become "ready" after each disconnect. I have no CEL and no codes shown on a standard OBDII reader. I last disconnected the battery a week ago Saturday to install the new window regulator, so I have 9 days of driving to work at 28miles round trip, for 252 miles total drive-time since the computer reset. I searched the forums upside down and backwards and figure it could one of two things: 1) I need to keep driving (some say up to 1000miles?! What??), or follow the Drive Cycle I found on a random site (see attached). I likely have not kept the car in the rpm region the drive cycle is suggesting. Attached is the cycle I'm referring to. 2) Or maybe I accidently disconnected or broke a vacuum line from the Changeover Valve #2 for the Intake SAI (secondary air injector) whole ripping apart the top end to get at the AOS. But if that was the case, wouldn't I see a CEL and codes thrown? I did the AOS work over three weeks ago, and it's never run better than it does now! So I figure a broke vac line from the vac reservoir would certainly cause issues. Or even if the line from the changeover valve to the SAI one-way check valve was broken I would also expect some sort of issue. But nada, it runs great. What say you? I also attached a cool vacuum diagram I found online that Ahsai here on the forum did. (One more thing: when I did the AOS, I saw that the previous owner had never hooked up the intake resonance flap actuator to the changeover valve #1. Instead, that valve orifice was connected to the power steering pump vent tube, and the resonance actuator was not hooked up at all! WTF past-owner?? I've been running it like that for 8 years. I'm sure that's another reason it runs better now!)

It's been a while since I've seen emissions readiness issues on my cars, but I thought the emissions readiness was Boolean - true or false. Your drive cycle needs to be completed as you indicated; the issue with the secondary air injection pump is a separate problem (that will also keep you from passing smog). I think you're correct - that you need to deal with both issues. I do not know if you can complete an emissions readiness (drive cycle) until the SAI pump is functioning normally. Do you hear the pump running on cold start in the mornings? As you probably know, it's in the left rear corner of the engine bay and sounds like a crappy vacuum cleaner. If it's not powering up at all, check the electrical connector. Not having the pump connected won't make the car run worse; it just keeps the catalyst from getting up to temperature quickly. If the check valve is stuck, some contact cleaner may do the trick.

Yep, thought it could be something with the pump too, but it 'seems' normal. I hear the pump kick on when I start the car cold, and 2+ minutes later it goes off and I drive away. (For 8 years I've used Macster's recommendation of waiting to drive until the pump turns off). Are there tests I can do to check that the pump and air valves (electric and pneumatic) are OK?

Here's some info from an old Renntech post about 986 emissions readiness: "For some unknown reason, some of the earlier 986 cars (2000-2001) are very slow to reset the secondary air injection system's I/M Readiness flag, sometimes taking as much as 100 miles or more to reset after code clearing. People have tried a variety of techniques to overcome this, often with very limited success. If you can hear the system running on a cold start, and there is nothing else organically wrong with the car, I would just put some everyday miles on the car until you see a clear I/M Readiness test, then take it in for inspection." So, maybe it is just a matter of putting some more time and miles on the car.

Hmmm, maybe it is. I've put 250miles on it since the battery reset, so I would have thought it would have gotten it's brain back by now. Sheesh, what's with these cars? If that's the case (which I actually hope it is) I'll be delinquent on my smog cert by the time this thing resets!

You can pay the registration now and deal with the smog later. You won't get your new stickers obviously until you get the smog taken care of, but you can avoid the late fees by paying now.

Very true, good point!

What scanner do you have? If your scanner can read the O2 sensor voltage in real-time, you can follow post #6 here to check what problem(s) is in your SAI system https://rennlist.com/forums/996-foru...l#post11746570 Also, most scanner can read the readiness codes so at least you can read that before you even try to get your car to smog so you won't have surprises. And yeah, that SAI photo was taken by me

Thanks Ahsai, for the response AND the vac diagram! It was that diagram that showed me someone routed my lines wrong. I have the Actron CP9575. I was looking thru the booklet and it does quite a bit, more than my car will allow (since it's a pre-'05 car). I scanned the car and saw that "inc" next to the secondary air system readiness line, so at least I'll know when it's 'ready'. I'll follow that link and see what I find. But my question still remains: wouldn't the computer throw a code if something was actually wrong or broken? Can one of the valves or other part physically not function and the car won't throw a code? I have 10 days to get retested on the $60 I already paid, then I have to pay again. I want this fixed soon.

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Re your question, yes the car should throw a code eventually if something in the SAI is not working properly but that may take some time to trip the CEL. The fastest way is to monitor the O2 sensor voltage and see for yourself whether the expected pattern that the DME is looking for is there. e.g., if the SAI valve is not working despite a running pump, you would see the O2 sensor voltage will not stay low during the cold start. It's also possible as Schnell pointed out sometimes you just have to put more miles on it before the SAI will be ready.

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Thanks Ahsai, this is a great data plot you have on that post! Looking at the data after I'd driven the car to work this morning, I see the same fluctuations on one set of O2 sensors, and none on the other set. It looks like that is all operating properly. See attached. I will take a look at these numbers during a cold start when I leave work today. I can't take a datalog with this scanner and plot it verses time, but I will take manual notes of the O2 sensor's values every 10 seconds or so and plot it out. If those numbers look amiss, maybe that's where the issue is (during cold startup), and the air isn't getting into the engine due to a bad pump (#1), bad solenoid valve (#18), or bad pneumatic one way valve (#11)? Those number are of the parts shown in the blow-apart I got from your link and re-posted below.

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just keep driving. it took a while for mine to get into readiness mode after my rebuild. after I passed my emissions test, it threw a code on the way home, but I had passed at that point and wasn't all that upset. my code was related to a vacuum leak.

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You're welcome and thanks! The O2s12 and O2s22 are the two post-cat sensors for bank 1 and 2 , respectively (first digit after the "s": 1= bank 1, 2=bank 2. Second digit: 1 =pre-cat and 2 = post-cat). They look great for being steady at ~0.7v. The ones that are more important for the SAI are the pre-cat sensors O2s11 and O2s21. For the SAI flag to set, the DME looks for two things: 1) During cold start, the precat sensors stay close to 0v when the pump is running. i.e., O2s11 and O2s21 should stay close to 0v (except for the first minute or so when they are warming up). 2) Warmed up engine during idle, you will hear the SAI pump turns on for a few seconds and again the DME looks for the 0v reading. Plotting by hand is fine. The info will tell you so much about the condition of the O2 sensors, the cats, and how the whole SAI system is working. You can disconnect the cable at the engine bay "+" jumper terminal right above the a/c compressor. Then your starter/alternator cables will be isolated from the battery. Yes, those will be the parts to go after IF your readings are off per above.

Excellent, thanks Ahsai and AWDGuy. I'll grab some more data, and hopefully it looks good. If it does, hopefully the car will finally ready itself after more driving. I should have scanned the car before I went to smog it, but I always figured there'd be a CEL if anything was amiss that would cause the car not to pass smog that wouldn't automatically reset within 20min of driving. Oh Porsche...

If it makes you feel any better, that emissions readiness crap applies to all OBD-II cars with emissions gear, not just your 911.

Ok, so here's a crappy dataset of the O2 sensors on a cold startup. I forgot my stopwatch, so I just kept counting to 5 and taking a picture (5s sampling time) of my scanner, and then plotted the numbers manually. I just bought a datalogger which should be here tomorrow, so Tuesday morning I should be able to post better data. My reader shows "O2Sxy", and I'm assuming X represents the sensor number since it's after "S", and Y represents the bank. Yes? O2S21 goes to zero pretty soon after startup. It's 'mate' doesn't. Hmmm. As soon as I heard the air pump turn off, O2S21 started to climb. Thoughts Ahsai? I also took out the alternator to get a better view of the solenoid and pneumatic valves. Pneumatic valve tested out OK: I tested it by blowing on its inlet tube that the air pump connects to. Couldn't push any air thru. I then drew vacuum on the valve's vacuum port, and now I could blow air thru it. Electric solenoid valve tested out OK: I tested it by sucking the port connected to vac, and it was blocked. I applied 12V to the valve and I could now suck air thru it. So it appears that those valves are working correctly, which is a good thing. But that data. Hmmm. Still no CEL and all the other monitors (Cat, O2, etc.) pass and say OK.

Excellent plot. For the O2Sxy coding, please re-read post #13. I've already explained there (x is the bank # and y is the sensor position: 1=pre and 2=post). I think you've found your problem. The SAI doesn't set because your orange and blue curves are not staying low enough during the first minute of cold start. Are you sure your legend of the curves are correct? It looks more like to me yellow and grey should be from one bank and orange and blue from the other. That would have made a lot more sense. The yellow is the pre-cat and grey is the post-cat, from the same bank and their readings are spot on. Orange and blue both don't "see" enough fresh air on the same bank, possibly due to carbon build up at the exhaust. You would need to remove the header and check the SAI ports to correct this problem. But first thing first, if you can confirm once again the legend of the curves, we can do a more accurate analysis.

Thanks Ahsai. You're helping me narrow in on the problem. For the "XY", I understand there is a pair of pre-cat O2 sensors, one on bank 1, one on bank 2, and a post-cat pair, one on bank 1 and one on bank 2. What I'm not sure about is how my scanner is referencing them with their nomenclature. Am I assuming correctly that O2S12 means sensor 1 on bank 2? I just double checked all the pictures of my scanner that I took the data from, and all of the O2 sensors are correctly labeled in the graph. Strange... I've never taken the headers off, but I have removed just about everything off the back end of the car to get at the coil packs a couple months ago. Is it a simple process? And I just poke-out any carbon buildup that I see in the SAI ports? Where are the SAI ports? Are there holes in every exhaust port in the head, or just one on each side? In the last two months I've changed the plugs, coil packs, AOS, water pump, thermostat, starter, and window regulator. Man, now more work. : / And I thought Alfa's were bad!

Ok, seems like I'm not getting my point about the "XY" across despite trying it 2 times I'll just list it out for you this time. Note these are per the OBDII standard and that's also what your scanner SHOULD be using. O2S11: bank 1 pre-cat O2S12: bank 1 post-cat O2S21: bank 2 pre-cat O2S22: bank 2 post-cat Suppose your scanner is good and the graph labels are correct. Here's what I don't think it makes sense. The red will be bank 1 pre-cat and the gray will be bank 1 post-cat. Why the post-cat sensor was able to detect the O2 after 40s yet the red pre-cat still can't detect the fresh O2? One possibility is you have a worn out bank 1 pre-cat sensor. Also, the orange line will be bank 2 pre-cat which detected the O2 perfectly but why the blue bank 2 post-cat didn't? One possibility is you have a worn out bank 2 post-cat sensor. I would like to see another set of data from a different scanner and if they show the same, I think changing out the O2 sensors first (~$100 each Bosch direct replacement) may not be a bad idea. However, if it turns out what I said was right in the previous post, you will be looking for SAI ports. Once the header is removed (just 6 to 8 header bolts, best soaked with Kroil and remove with impact gun), the port or holes are right there for you to see and carbon buildup will be obvious (if that's the problem). There was a thread I helped another gentleman and it has very nice pictures of the ports once the header is removed. I'll see if I could find that thread.

Check out this thread for photos of the header and SAI ports http://www.renntech.org/forums/topic...comment-277522

Thanks for listing the names out, I couldn't find that anywhere in the previous links you gave, only talk about the different banks/sensors. That's exactly backwards to what I was thinking, so I'm glad I see it correctly now. I don't know what to think about the O2 sensor data. I don't want to go spend $200-$400 just to find out it was carbon build up, so I'll wait for my datalogger to show up tomorrow, take some data on Tuesday morning, see what it says, then likely take the exhaust off Tuesday night regardless since I know there's got to be some issues there. Thanks for the link showing the ports. I also found a boxter post where the guy flushed the whole SAI system with Sea Foam and a little hand pump. I'll likely do the same. I just wish it wasn't a rush job cause of this smog thing; why couldn't Porsche throw up a CEL if the monitor isn't readying for nearly 400 miles?? Then at least I'd've known. Oh well, time to dig into the car yet again.

Yeah, I agree we should collect more data first. If you suspect the sensors, you can switch them between the banks and see if the readings follow the sensor or the bank. That will give us even more data points. In any case, seems it's a good idea to pay for your registration first to avoid penalty as I think it may take some time to diagnose and fix your problem.

Re the CEL, it's possible your system is at the edge of failure and it intermittently passes some of the tests (within the SAI tests) . When some of the tests fail, the DME is giving it another chance before it flags the CEL. There are quite complicated algorithms inside the DME to make it not too trigger happy and yet be able to detect persistent failures.

Ahsai you are the man, I don't have to deal with the smog requirements in MI, but if I did I'm glad you are on this site. Thank you for sharing all your knowledge and expertise in all things 996.

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Thanks! I'm always happy to spread the joy of diy and diagnostic

Soooooooo. Yesterday I got my datalogger and all the stuff to clean out the carbon once I drop the headers. I scanned the OBDII when I got home (like I've been doing every time I stop!) and guess what? Secondary Air System is now ready! Even with that not-great-looking O2 data, the system is finally green across the board (SAI was the only one not ready). And it only took somewhere north of 300 miles (it wasn't up to 400 yet like I'd thought). Sheesh. Never a CEL, and the car has been running better than it ever has after all the work I did. Anyway, just got my smog certificate and Mr. California DMV is happy. I will still take some data on my O2 sensors in the next few days and plot it out, as the system is obviously not 100% healthy. But now I've got two years to find the time to pull the exhaust and clean out all that carbon and/or replace any O2 sensors.

Heh. If it's any consolation, Mr. Murphy's Law stipulates that if you had not ordered the datalogger, the problem would not have cleared on its own. You were screwed either way.

Sorry if this does not help... I did not read all the posts... If your looking to reset the Readiness Monitors this is the work sheet that I came up with from searching the net last year: Start engine, idle cold for approx. 2 min, 10 secs. Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs. Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins. Decelerate and come to a stop. Idle in gear* for approx 5 mins. 1..As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump andEVAP purge. 2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge. 3. Hold at a steady state speed of 55 mph for three minutes. OBDII monitors EGR, air pump, O2 sensors and canister purge. 4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions. 5. Accelerate back to 55 to 60 mph at half throttle. OBDII checks misfire, fuel trim and purge again. 6. Hold at a steady speed of 55 to 60 mph for five minutes. OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions. 7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge. just hold the following RPM ranges from 2-5 minutes: Idle 1500 2000 2500 3000 Idle the checks usually happen before the 5 minutes is up, but without a scan tool hooked up you won't know when it happens.

Heh. Now you just have to find a place in SoCal where you can go 55 for three minutes without rear-ending someone or getting shot.

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That's nice. It's quite possible since the system is at the edge of failing so sometimes the SAI tests pass and sometimes they don't. Good you caught it when the tests passed. Let us know if and when you have more data to look at.

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And a co-pilot who can keep track of where you are in the process.

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5CHN3LL LOL!!! That cracked me up. So freaking true. Get me out of this place... Joe-1972, thanks for the info. I did find a similar process that I posted, but yours has more details. If it can get the car's monitors to ready themselves sooner than 300-400miles of driving, it might be worth getting shot at. Ahsai, I agree, I think it was on the hairy edge. This scanner has already paid for itself over and over. The datalogger will come in handy and help dial in on the health of everything in general. I'll post more to this thread when I get more data and dive in to clean out the SAI passages.

I have a 98 boxster I purchased just over a year ago. I now have 140,000 after driving it all summer about 5K . I had codes of P0102 MAF and I replaced it with a non Bosch unit. The car just passed SMOG and the CEL came back about a month later. Now it was P0441 for the EVAP emission. Since then I replaced oil, the spark plugs, the evap valve at the fuel tank and under the manifold. Also a smoke check performed. The CEL stayed off for 2 weeks. Now the code is P1411 and P0410 for the SAI. After 3 days the CEL went off. The mechanic suggests a vacuum valve of some kind, which can only be found with the computer. The car sometimes makes a howling noise at startup. Maybe you can point me in the right direction I have to SMOG again in about 45 days.

Hey CalSierra986, while I can't speak to all of your codes and how they all likely interplay into what your exact problem is, it does sound like you could have a couple issues, some of which you may have fixed with the things you did. The SAI codes show you have a problem with both banks. That could be the air pump is not functioning, not being triggered, the SAI check valve is blocked, the changeover solenoid valve that opens the SAI check valve with vacuum isn't working, there's a vac leak, or you have majorly blocked SAI passages. You can test most of these without digging too far into the engine, with the SAI check valve and changeover valves being checked by first taking out the alternator to get to them. My SAI air pump also 'howls' (some say it sounds more like a buzz saw) from time to time on startup, but the pump still works fine and has been making that sound since I got the car over 7ish years ago. You can take off the outlet line off the pump (located in the bottom left corner of the engine bay in front of the overflow tank) and cold-start the car and see if it has air coming out of the pump (not the hose).

I disconnected my battery (while working on some audio stuff) and immediately realized I needed a smog check within a few days. I didn't have much drive time on the car - less than an hour - so I was expecting Durametric to report that the car wasn't emissions-test-ready - but it WAS, and my '99 passed with flying colors. Posting this so peavynation (OP) has a data point for comparison; I think your plan to dig into the SAI system is sound before you have to worry about this again in 2 years. The guy in front of me last weekend when I got the car smogged failed due to not-ready-for-testing state; the shop charged him $50 for the "test," which I thought was a little steep for the 5 minutes the tech took to pull the car into the bay, connect the OBD-II cable, and determine the car wasn't test-ready. It definitely would have been cheaper for the guy to use a cheap scanner or a wireless dongle and Torque to test that ahead of time.

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P0410 points to the secondary air change over valves. One is electric and the other vacuum operated. For the electric value see this link: http://www.pelicanparts.com/catalog/...FULEMI_pg2.htm For the other valve see this link: http://www.pelicanparts.com/catalog/...FULEMI_pg2.htm If you elect to replace these be aware the hose from the pump to the air change over valve and the hose from the air change over valve to the non-return valve can be bad. And if you are not very gentle and very careful you can make one or both of these bad.

This is an excellent,helpful thread. I offer one very specific comment that may help others . For the 2001 cars there is a very difficult,obscure Secondary Air Injection ( or S.A.I.) "Not Ready" problem. This is also called "Inc" or "Incomplete". There is no MIL/ Check Engine nor any pending codes. You won't fail a Smog Test even in California with this problem - your car will be "Declined". Which is nonsense because you won't get a Pass test certificate and you'll be unable to get tags for your car. But do pay the invoice !! You will be told to just drive the car. I have been just driving mine for 2400 miles and 20 months. The SAI according to Durametric and Foxwell NT520Pro is still Not Ready.. The S.A.I. system works perfectly by any diagnosis O2 sensor voltage ahead of Cats at start up. air flow of SAI pump,exhaust posts in head are clean,all SAI hoses and connectors are new/upgraded.Check valve receives strong vacuum while SAI pump operates. Using an emulator(for diagnostic purposes only) in the O2 sensor circuit makes no difference. The Referee refuses to test the car insisting it goes to the Porsche dealer for repair. That is a blank check because they speculate it might need a new ECU ,a new SAI system etc. Really the dealer doesn't want to attempt obscure repairs on an old car. The reflash with ROW option is eliminated because the new (DAD) smog machine will detect the abnormal code and your car will fail for 'equipment tampering" One option is to get a reflash to stock ,hoping that there may have been some bug fixes in the latest reflash . Is this reasonable ? Another is to get an Indie with PIWIS to 'force' a Ready status even temporarily and then Smog test immediately.. This thread may be a good spot to document an effective solution to this problem. It affects very,very few 996 and 986 M96 engines so the usual Internet resources are unhelpful. Any ideas/solutions ? Thanks.

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That's some interesting info Schnell, thanks for posting. I wonder if what you're describing is something that a car has from the beginning, or if it gets worse over the years until this 2500+ miles of driving and still no recovery? I was just thinking about this thread last week and all the issues with my computer not resetting. My airbag dash light has been on for nearly 3+ years because I fear resetting it will reset the entire computer and I'll end up having to go thru this mess all over again, and maybe not being so lucky as to have it finally recover in "only" 300-400 miles of driving. (I had to power the car up with the door's airbag removed when I replaced/adjusted a new driver-side regulator, hence the light). After reading Schnell's post, I'm even more hesitant to reset it! I wonder if @Macster knows about this; he'd be the one I'd bet money on if I had to choose.

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Airbag light reset did not reset any emmisions codes in my 2000. Its in a different area of the programing.

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Thanks De Jeeper, that's good to know. I was told by the smog guy at the time (that supposedly does lots of euro cars) that the air-bag light is a "ghost code" and only the dealer's PIWIS can clear, but sometimes a Durametric can. What did you use to clear the code, and does the airbag come up as its own error that you clear independently hence it not affecting the rest of the systems?

A local indys older snap-on scanner. Any decent shop scanner can do the airbag. Generally emisions codes r stored in a different spot because of federal regs. It would drive me crazy having the light on. Hope it doesnt reset your system.

Used my Foxwell 530 to clear an airbag light. Can't remember the exact details, but I think it was under a different menu than the other codes.

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Thanks guys, this is great. De Jeeper, yeah I lasted about 8 minutes with that light on before it drove me mad. I went into my shop and fabricated a little black plastic shield that slips into a existing seam to hold it and perfectly blocks that little round light; I don't even notice it anymore. Finally I can get it reset without worrying about the smog crap! Merry Christmas guys.