CSbox03s

About a 1.5 weeks ago I went for a ride in my '03 986S and my "PSM off" light and the "ABS" light both came on together at the same time. I did not touch the "PSM" dash board switch to turn it off, but double checked the switch and nothing happened with the lights remaining on. I then pulled over about 5 minutes later and rebooted the car. The light went away for the next 2 hours of driving. During that time I turned PSM off and on without any issues or lights remaining on.

Anyhow, so last night I took it out for a spin to check on the issue. I started the car, let it warm up and no lights. However, about a minute later when I dropped the E brake the lights came on again. I rebooted, lights were off and then they came on about 5 minutes later and stayed on for the remainder of my 30 minute drive. The car drove fine and there were no diferences in the handling.

Any suggestions, comments, experience with the problem and/ or questions?

Thanks,
CSbox03s

bcr4d

I had the same problem with my 00 C4. It turned out to be MAF sensor.

UCrazyKid

since the PSM uses the ABS system and sensors to operate it is likely you have an ABS system problem only. Since it is intermittent it is likely to be a bad sensor or sensor connection. Possibly the sensor is dirty or blocked by debris. Try cleaning your wheels, brakes and hub area on all four corners. Might help, might not.

Try getting the codes pulled with a reader, might help.

CSbox03s

Thanks for the input. I assumed it was an ABS issue since when the lights are off the PSM works fine. I am in the process of getting the codes pulled in the next week or so. I will post my findings.

an02boxster

Had the same issue, MAF sensor fixed mine.

CSbox03s

Did any of you have the check engine light on in addition to the "PSM off" and "ABS" light.

wwest

Mine acted the same way and it turned out that I needed a new battery.

bcr4d

had check engine, psm & abs. MAF fixed the problem.

AudiOn19s

I had this in the past too. Sounded like the craziest thing to me that I'd get those lights and it'd be related to MAF sensor. I cleaned the sensor and they went away a couple of starts after cleaning it.

Andy

Loren

Both a bad brake light switch or a bad MAF can cause both lights. Brake lights are easy enough to check.

CSbox03s

AudiOn19s . . . That is what I am thinking. I threw an OBD II reader on the car to see if there are codes for the MAF and no codes were thrown. I will check the lights and try to clean out the MAF before I get the car checked out next week.

All . . . Thanks for the input. Extremely helpful and good to know this isn't a code for "car about to self destruct." Thanks again.

UCrazyKid

Sorry, I decided to choose logic to answer the problem. Looks like it is probably the MAF, what was Porsche thinking? Making it impossible to diagnose the car from the warning lights alone so you HAVE to go to the dealer? Crazy

an02boxster

I think that if the MAF is not working then the engine can not be controlled by the computer so... the PSM turns off since it won't be able to control engine speed properly. Just a guess.

hwk72

Did you check your tire pressure? I had an air leak on one of my tires which triggered the ABS light to come on (I don't have PSM); tire pressure difference on front tires was 15 psi.

CSbox03s

an02boxster . . . I was thinking along the same lines.

Anyways, sounds like I have a list of things to do this weekend! I will take the time to investigate all the suggestions by everyone summarized below and will post results.

In order of least to highest difficulty:
- Check brake lights (weekend car, so haven't checked yet)
- Check tire pressure
- Check Battery
- Check and Clean ABS sensors
- Clean MAF sensor

I will add as people give input.

Thanks again,
CSbox03s