ABS and PSM lights went off on dash while driving

[Gary S K Lee]

ABS/PSM light went off once while driving...what could cause this to happen?

Edited April 21, 2014 by Gary S K Lee

[Loren]

Is your car a 4WD (C4 or C4S)?

Wheel slip can cause this and is more common with a Tiptronic. As long as it clears it is nothing to worry about.

If it does not clear then there are other possibilities - including a bad MAF, and wheel sensor issues. If it happens again and they stay on - it would be best to get the ABS/PSM fault codes (you will need Durametric, or a Porsche PST2, or Porsche PWIIS tester to read these faults.

[Gary S K Lee]

mine's a 996 C4S with tiptronic...i googled about this PSM/ABS light thing and it's a really common problem. Some say it's the alternator not giving enough ampere and might even cause the engine to stall.

Edited April 21, 2014 by Gary S K Lee

[judgejon]

the search engine here will be your best source.

this issue can be caused by mismatched tires? Have you just changed tires? Are you using different tires on front/rear? All tires should be of same manufacture and, if Porsche rated, should be of same rating, like N3, etc. This would cause the system to engage on corners and turns. But you say the performance of the car was not affected.....

Alternator can be affected if the PSM does kick in too often. Alternator can overload, and if so then the car will simply stop running and then refuse to restart. Then it's new, or rebuilt, alternator time.

If its the tires, you could turn off the PSM system, and live with the yellow light telling you its off. If it's not a tire issue, follow Loren's advice.

Good luck.

Edited March 20, 2014 by judgejon

[Gary S K Lee]

don't think that's related to tires as the light went off only at very slow speed.

Edited April 21, 2014 by Gary S K Lee

[Ahsai]

As Loren said, best is to scan it with durametric or alike to retrieve any codes. Otherwise it's diagnosing in the dark.

[Rob001]

I had the same intermittent ABS/PSM problem.

Checked for error code and got 4205, front left speed sensor.

Turned out to be a broken wire in harness from speed sensor to ABS module.

This is a commom problem in lead at grommet which is pressed into the front shock.

Could not be your problem but check for error code first as above advised.

[Gary S K Lee]

I will surely have it check on monday...

Edited April 21, 2014 by Gary S K Lee

[bcrdukes]

Gary,

I recently had the same problem. I purchased a Durametric cable and pulled code 4460 - Pressure Sensor.

I did the basics first - checked the brake light switch = no go.

Check battery voltage - it was low. I charged it up over night and it has held a good charge since (previous owner did not drive the car much.)

So far, so good. I haven't had any fault codes pop up - yet! Get the fault code pulled first and report back. From my searches, Loren has posted a comprehensive troubleshooting guide in several posts and I don't think it has failed anyone to my knowledge.

Good luck!

Edited March 28, 2014 by bcrdukes

[Gary S K Lee]

went to my garage and found out there's an ABS code stored in the computer...had it reset and now the lights haven't been popping up at all. Im glad i have my problem free C4S back!

Edited April 21, 2014 by Gary S K Lee