2001 996 CEL Troubleshooting

Please Help!!! I just purchased a 2001 996 a week ago. It ran fine for a few days, then one night I tried to start it up and the CEL started blinking, then solid, then blinking, etc. Since then, the idle is pretty rough, especially with the a/c on. I put the code reader in, and I got P1130, P0300, P0301, P0302. The car has 90,000 miles on it, and here is the rest of the story. 1. The night before, it rained pretty hard. It may have been the first time the car has gotten wet in months, as the previous owner kept it under a carport. My concern with wetness revolves around possible coil failure. 2. Also, I performed a oil drain plug swap. When I bought the car, I asked the owner to perform an oil change in my presence, so I could check the filter for particles (IMS). The filter was fine, but the previous owner had to reuse the plug gasket, so the car developed a slight drip from the plug. I ordered a new plug, and simply removed the old one, and shoved the new one in and tightened it. Some oil came out, but it was about 1/4 of a quart, so I replaced that amount of oil with new oil. Also, no more drip. Any help or ideas would be greatly appreciated.

Also, it appears that the P0301 code was pending, and was able to be cleared by the OBD2.

Rain or dampness has nothing to do with the way the car is reacting. I know nothing about codes. The thing I would check is when the last time the spark plugs were changed. (addition here) I would like to retract that first paragraph because of the posting from Macster. Now that is big news to me that a lot of rain would effect the starting of a Porche engine or any other engine for that matter unless the rain was landing directly onto the opened engine lid. I stand corrected and back out of this thread diligently. .

sounds like cracked coil packs

Does it make sense that coil pack problems would show up after a big rain?

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Well, I'm going to have to disagree with Hurdigurdiman...maybe. First, my disagreement: I believe leaving the car out in the rain has everything to do with the symptoms. Two times now I have left my 996 (Turbo) out in the rain (overnight or during a full day of heavy rain) and both times upon cold engine start the engine was rougher than usual and the CEL came on. P0300 and a couple of other P030X error codes, all misfires. The coils are original and the car has over 92K miles. The plugs were changed a few K miles back and the Porsche tech reported the coils looked just fine. I'll tell you what the tech told me the 1st time this happened to me: Clear the codes and drive the car. If the coils are truly bad the symptom will come back. I went a bit further and several times left the car outside overnight and the misfires never resurfaced until I left the car out in a heavy rain storm this last 'winter' here in the SF bay area. I will add though a caution and that is if at any time the engine starts to act up, CEL or no, run rough, lumpy idle, make noises, smoke, anything out of the ordinary shut off the engine and do not run it again until you have lined up a pro Porsche tech who will advise you. I do not expect anything serious is lurking, but better safe than sorry. Where I could agree with Hurdigurdiman is that P1130 code is a bit troubling. That's O2 sensing adaptation range 2 (cylinders 4-6) enrichment limit. The #2 bank is running lean and the DME added fuel and added fuel until it reached its, well, enrichment limit. This can come from an intake air leak, a too low of a fuel pressure (at least on that side of the engine), fuel injectors contaminated, or the fuel supply too low. That the other bank didn't throw a related error code suggests the problem is not common to both banks which lets out the fuel supply being too low. However my info is misfires should not be logged if the fuel level is 'too low'. So this kind of lets the fuel supply level cause go by the wayside. It could just be one bad injector. The DME can only monitor a bank's worth of cylinders by the bank's #1 and #2 O2 sensors so if one injector is contaminated (and not flowing enough fuel) the DME will add fuel to all injectors of that bank. This can lead to rich misfires of the other (healthy) cylinders. A blinking CEL signals rich misfires, misfires that arise from a condition that can dump raw fuel into the converters which can overheat and ruin the converters. Thus you may want to get the car to a shop rather than just clearing the codes and driving the car around some more. The extra fuel in the healthy cylinders can contribute to accelerated wear and this fuel can dilute the oil with risk to the engine from this diluted oil. Added: If you pushed me to name a suspect cylinder, and its suspect injector, I'd have to say "3". The misfires occurred in the #1 and #2 cylinders. These may be the healthy ones and they misfired from too much fuel. Sincerely, Macster.

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YES! and also check the area around the battery take off the plastic covering there and look to see that all the rains are free of leaves, dirt acorns etc.

It's funny you should mention the battery. When I give the car gas (in neutral), or turn the a/c compressor on, it almost appears as if the dash lights dim a bit. Not much, but just a bit for a moment. I don't have much experience with a 911, so I wasn't sure if that was normal or not... P.S. One other thing... During the heavy rain, the car was sitting in my driveway with the rear spoiler up (in manual), but the hood closed. Thanks again for all of the help.

The rain stopped last night, so I figured I'd test my theory this morning. I read the codes again, which were: P1130 P0302 P0301 - Pending I erased the codes and started up. There was a rough idle, and the CEL started blinking again. Shut it down, read the codes. Now only 1 code: P0302 - Pending Erased codes again... Started again. Noticed the idle was completely smooth... Waited for the light... It never came on, so I took it around the block (just over a mile). The car ran fine... no CEL... But, now it's raining again. I may wait for it to get real wet and see if the CEL comes back. Thoughts?

The is a voltage meter on the left side of the dash. Watch it! If with the ignition on(but car not started) you will get the battery voltage should be near 12V After starting the car you will get the alternator output. Initially after starting the car it should go to 13.5 or 14V for a while till it gets the battery charged up from the starting drain. Watch this volt meter when the AC goes on and off and when you add lights heater fan etc a little dip in the voltage is the lag before the voltage regulator tells the alternator to charge the system. Could be normal to have a quick dip in voltage or the begining of the voltage regulator failure. You can just change the voltage regulator(but the alternator has to come out) Or just replace it all(alternator) when it goes. A little heat from your engine should dry out the coil packs pretty fast.

Im thinking coil packs... more so, the O rings, they may have cracks on them. I would check that vicinity.

I'll chime in with coil packs as well.

Just an update The car was still running fine today. However, I noticed that the coolant is well below the minimum line in the reservoir. Now I'm concerned I could be dealing with a head gasket leak (or worse). The reservoir is the .03 revision. If I had coolant getting leaking in the engine, is that a situation that would get better on its own? Can that cause the CEL for misfires? Thanks again... again...

Good point... The CEL was cleared, the light didn't just go away. One other point... The low coolant light has never come on and the temperature is fine.

So I just brought the car to my local Indy. They are not open today, but they will get to it first thing tomorrow morning. Once again, it was pouring down rain. The road was very wet and there were many puddles. On the way to the shop, I was in stop and go traffic (literally a red light every few hundred feet for a few miles). 3 or 4 times, when I stopped at a red light, the rpms would drop during idle and the CEL would flash. As I was looking for a place to pull over, the CEL always stopped blinking and the light wen completely out by the time I got to 20 mph. Does this make sense to anyone? My thinking is that the P030X codes make sense for misfire if I have bad coil packs getting wet, but my concern is that i do not understand the P1130 code. Additionally, the low coolant has me concerned that it could be related to the P1130 code and possibly be from a more serious problem. I added coolant this morning, and it didn't take very much. I would say the level was 1" below the minimum mark on the expansion tank. Any thoughts are much appreciated...

you may have multiple problems... o2 and misfire... explains why its running like crap.

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The coolant can be low due to based on my experience with both of my cars a leaking cap. The cap leaks a bit of vapor when the engine is shut off hot and this over time will have the coolant low. In my Boxster it got low enough the low coolant light started flashing. The cap is not that much. Get a new cap (part # ends in 03 or 04) and before you install it with the engine *COLD* clean off the tank fitting where the cap screws so the cap and the seal in it have clean surfaces with no dried coolant residue to possibly interfere with the cap's seal. If you suspect a coolant leak at the head gasket you need to look in the coolant for signs of oil (black drops of oil floating about) or drain the oil (just the filter housing is enough) into a *clean* drain pan and look for signs of coolant. You can have the oil analyzed for any signs of anti-freeze compounds. What you find determines what you do next. However, only a few times have I encountered low/bad battery with my cars and never did the engine act up. Well, check that. It did act up when the battery got bad, it acted up in that it didn't not start. But just before this even though the power was low enough that as I was cranking the engine the dash lights nearly went out and the door windows were dropping/'raising like ghosts were playing with the door handles, the engine once it caught and started running the engine ran just fine, with no signs of any problems. But that doesn't mean every car that suffers from a bad battery will not have the engine acting strange. So you have to have the battery checked. Early in the day, and then at the end to see if the battery loses any power over the hours. Sincerely, Macster.

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My WAG is a coil is bad to have the engine react as it does in the rain. That the engine symptoms go away as speeds rise suggests this comes from the coil being dried out from the heat of the engine and the fact air flow carries the rain over the engine compartment. Kind of a long shot but you have to check or think of other things, but be sure the engine intake is not somehow getting water in it. But the odds are one or more coils is bad. So get the misfire cause diagnoses and taken care of first. Then see if the P1130 comes back. 'course there's no reason why you can't have the tech check for any causes of the P1130 while the car in the service bay. Maybe an AOS is going bad? Or the oil filler tube cracked. Sincerely, Macster.

Thank you so much for the replies. I'm starting to feel a little better about the car (although I'm anxious to see what the Indy finds in the morning). As stated above, the car has 91,500 miles. Would it be wise to replace the water pump and AOS while the shop has the car? Is there anything else that I should consider replacing at this time? I have little experience with the car, but I do know the clutch is new (unfortunately the IMS is old)... Thanks

What you get done/updated/replaced when the Indy has the car would all depend on records that came with the car. What was done and when it WAS done. All the usual things that needs replacing on the 996 should get done. I mean, it has done a good milage but should be good for another 100,000 provided the correct work is done on the car and engine.

I have no records of any replacements, other than the clutch, RMS, rear struts and expansion tank. I was planning on having the serpentine belt replaced since that should be dirt cheap. I was debating on the water pump and AOS based on the devastating possible effects of their failure.

In post #8 you mentioned that you were parked with the spoiler up in manual mode. I'm just a newbie to the P-car world but is it possible you've managed to get water into the inlet. Ditto when you were driving in the start stop traffic you described later.

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Neither the water pump or AOS are cheap jobs to do. I would be reluctant to have them done without any indication they need doing. Now I might have a different opinion if the engine has to come out of the car. At which time the labor to replace the water pump and the AOS sort of disappear into the cost of the engine R&R and of course whatever prompted this to be done in the 1st place, unless the tech charges you full labor for both jobs. (Ouch!) My 02 Boxster's water pump lasted 172K miles. I had some sign something was amiss though. Upon cold start and as the engine idled the engine developed a low faint grumbling noise, nothing really scary. I identified the noise as coming from outside of the engine by removing the serpentine belt and staring and idling the the engine from cold for a moment or two, just long enough to be sure the noise was not present. This confirmed the noise was not coming from inside the engine. (On second thought, I guess the noise was a bit scary until I had this confirmation.) Then I shut off the engine and checked the accessory drive pulleys/shafts and idler for any play. I had to go around them several times. The water pump was the only one that had any play compared to the other drive pulleys. There was some white residue on the pump housing which is a sign coolant is leaking and drying. Oh, another sign was the very fresh belt had developed a sharp edge which arose from the belt rubbing on a pulley which it should not do. Anyhow, I had the car flat bedded to a nearby (15 miles) dealer and had the water pump and T-stat replaced. The Boxster goes through an AOS about every 80K to 100K miles. However, the current one is overdue based on some vague recollection of when it was done last. If you want to go the IMS bearing upgrade that is entirely up to you. I would not but some feel very strongly the other way. For me, I have decided (long time ago, when the 4 year, 50K mile waranty expired) to continue to drive my 02 Boxster as it came from the factory until I either get rid of the car or the engine blows up, or in some other way the car or the engine is not longer viable and I chose not to fix the car or the engine. In short, my motto is if it ain't broke don't fix it. But you can do whatever you feel is best for you, of course. Sincerely, Macster.

Got the call from the Indy today. They said the spark plugs were horribly corroded and the coil packs looked bad too. They looked over the rest of the car and said it appears to be in pretty good shape overall. They had trouble getting 1 spark plug out. They believe it was cross-threaded, but they were able to remove it and the new plug went in smoothly. I definitely got lucky on that one... They will deliver it tomorrow. I can't wait to drive it. I bet it will feel like a whole new car...

P.S. Thanks for all of the help with diagnosing this problem.

[QUOTE=Cmweber;9604690]P.S. Thanks for all of the help with diagnosing this problem.[/QUOTE I had the same exact issue and it was the coils and spark plugs. Replaced all of them, cleared the codes and the car is running like new.