ABS & PSM Failure lights

I just had my failure lights for the pSM and ABS go on. This is the first time I have driven the car since my last DE event 1 week ago. Anybody have any ideas what might be going on?

My first guess is you are low on brake fluid. Most likely, you wore your pads way down and there is now more fluid in the lines and less in the resevoir. Top off the resevoir and recheck for the lights. Make sure you also check your pads.

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Quote: Thanks for the reply. I checked the fluid reservoir and it was fine. The brake pads are on the low side but my pad wear sensor lights did not illuminate. The error lights have gone off and on intermittently over the last few days. I am going to change my pads out and see if this resolves the issue.

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Quote: There is a good possibility that the MAF may be starting to go as the traction control feature (PSM) needs load signal from the MAF to calculate how much power to apply or reduce. Usually see some DME fault too. PSM is just a function of power management in conjuction with application of ABS. You need to get the DME and ABS control modules scanned though as there could be a bad wheel speed sensor or other component that is failing. If the ABS control module is missing a wheel speed sensor signal or itself becomes faulty the ABS light will illuminate and traction control can not function properly. Maybe some trash in an ABS wheel speed sensor from the track possible also.

i was reading about this fault on Rennlist (there are many threads discussing this fault). it seems MAF sensor is #1 on list of possible faults, bad air filter is also mentioned. if you find resolution for this let me know. Mine goes off when i drive on a highway for about 15-20 mi. Driving at low speed through side streets, I can drive along way. roy

Both ABS and PSM flicker on off but mostly just on and durametric scanner says bad/shorted etc right wheel speed sensor. Cleaned sensor and inside wheel sensor area with no results. Just saying you could check it or clean also.

Thanks for the hint, Mother. I will clean the sensors and see what happens. I have already cleaned the MAF sensor, with no change. I will check the air filter; due to the symptom, failure only at high speed, it may be that dirty air is shorting the MAF under high air volume flows. i will post my results. roy

I will give it a try as well. I am running a Carbonio CIA with much higher air flow. Not sure if this is contributing at all. What is the best solvent to use when cleaning the sensors?

I am going to the Porsche/VW dealer to get my wife's Passat back. I will go in and ask the head tech guy and post his response.

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Quote: To determine if it is a MAF failure you need to get the DME control module scanned and look at the live data for MAF and fuel trims (TRA/RKAT and FRA) MAF air volume spec: 17kg/hr +/- 2 for 996 MAF hot film voltage: 1.2-1.4V +/- 2v engine running (key on engine off .9V +/-.2V TRA value should be around 0 FRA value should be around 1

I've had this happen to me in two different 997's. Both times it was covered under warranty. The Dealer said it is a switch (~$15 part) on the inside of the car (firewall) in back of & near the top of the brake pedal. The first time it happened (3+ years ago) they sent a flat bed wrecker to pick up the car. The next time (different car & 2 months ago) they said if you still have brakes (I did) to drive it in & most likely it was a bad switch and it was.

Ok. News from my dealer. {By the way, if you need a dealer in South New Jersey, Cherry Hill P/A has given me excellent service.} Last week, i had the turn signal box changed because the turn signal broke. In taking the steering column apart, the airbag clock spring unraveled. The part number is 996 652 211 00. This failure is giving signals that the turn sensors failed. So, there it is. Who knew, my dealer had the answer. Since the part is $232 plus installation, I guess I will live it for now. Roy 2002 C4S

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Quote: yep sounds like the classic brake light switch failure

JB Lifeguard - I have one of those airbag contacts if you are interested. I will sell it for alot less than they quoted you. And it is a DIY if you have a little aptitude and experience. There are some posts that have excellent instructions for it. PM me if you are interested.

Dharn55 I tried to PM you, but it may not have gone thru. i would be interested in the part. i will try to find the DIY instructions, but if you have them handy, or the link, could you please forward it. i got your PM, and if you send me your email, we can communicate that way. thanks JB LG

Hopefully a happy ending to my ABS/PSM problems. Brought my car to my dealer for diagnosis yesterday. When scanned, there were no specific error codes for the ABS or PSM. This led to the diagnosis faulty ignition switch. They stated it is a common problem with 02 and 03 911's. I had them replace it and all seems to be well again, knock on wood. Thanks for all of the responses.

I am happy you have got it fixed and better yet you posted what was done, that goes along way for others here.

FYI for people with this problem... if you have tire sizes which increase the overall diameter on the front or the rear and not both equivalent to eachother, this will cause the same issues, especially when your speed increase like freeway speeds.

Another random symptom I experienced was when I turned the ignition off the car remained on. This only happened twice over a month.

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Quote: I assume that when these idiot lights come on that the ABS/PSM is no longer working?

I tested the ABS by slamming on the brakes at speed and it still worked.

Tracked the car this weekend. No issues at all with ABS or brakes. The problem was fixed by replacing the ignition switch.

Great job and one less thing to worry about, I replaced mine also and my brake pedal no longer stalls the car.

Glad it worked out for you as well. A bit crazy how many things are affected by this simple switch going bad. Worse is that it cannot be diagnosed through scanning for a fault code.

Well...after 4 months of trouble shooting I fixed mine. I first started with the trouble codes. It indicated right front sensor not reading. I cleaned and switched speed sensors form L-R on the front. Did not help. (there is a way to test the wheel signal....with the sensor off, put an om meter where the sensor goes and spin the rotor, you should get a pulse). I read a post on this web site that said WIRES BREAK INSIDE THE HARNESS. Sure enough....after carfully splicing the harness open...alll the way up into the firewall...i found broken wires. PROBLEM SOLVED!!!!!

My ABS/PSM failure display went on when I was slowly accelerating from a stop. When I pulled over and tried to drive off it sounded like I was dragging my exhaust on the ground...sounds more serious than some broken wires. Would anyone know what that could be?! I had my rotors and pads replaced 6 months ago so I don't think thats the issue. Thanks!

bringing car to dealership tomorrow to see whats up, hopefully nothing major but with my luck, it'll cost me!

good luck!!!!

Shop cleared the code and tech said he's never seen a fault code "PSM-5525 torque transfer for DME." Said it didn't show up again, but could be related to my dirty K&N filtercharger, bad MAF, etc. Guess its time to start cleaning that filter!

well, my problem is still ongoing. replaced the clock spring ($300) and then took it for a long ride. lights came on after 20 mi or so. so i am taking it back to the dealer next week. any ideas would be appreciated. JB

Well, i think i got it sorted out. My car had two failures. The airbag contacts in the seats and the clock spring in the steering wheel. I had them both fixed, and it did cost a bit. I found some parts on ebay, (new, left over from other's DIY projects) and the rest i bought new from porscheoemparts.com. The prices there were sometimes lower than my dealers cost. the labor for the clock spring was reasonable, $70 or so. For the seat belt receptacles and wiring harness was not, $500. But, the dealer said it was a lot of work, and even by clock time it was well over 5 hrs. So, i have driven a bit - restricted by snow in south Jersey - and everything seems to work just fine. Tomorrow morning I have a 40 mi drive which should be the real test. The head wrench at the dealer said the ABS/PSM signal is generated by numerous faults in the system. The only way to get to it is a read out of the computer system and experience. On well, finally got the car sorted out - it took a year and several switches - and i look forward to no irritating errors showing up. all that's left now is to find some used coilovers. That's all from here. JB

What a ordeal, Ive been following this thread as I had the same ABS/PSM and I dont know what really fixed it for me but it has been gone for a good while and I hope it stays that way! Good luck tomorrow.

Problem gone. clock spring behind steering wheel, followed by sensor calibration. 996-652-211-00-M100 Contact Support for Steering Wheel Air Bag NOTE: Not for cars with M249 (Tiptronic), 996 Carrera 2/4 (1999-04), 911 Turbo (2001-05) feels good driving a car with no lights blinking at me. JB

Resurrecting an old thread - I had the ABS / PSM failure problem. Replaced my brake switch by the pedal and problem went away.

100% MAF or total Tail-Light Failure. Every time I wash my car I always get PSM/ABS Lights, I just restart and they clear.

every time i wash my car i get a low oil level measurement

Wanted to revive....I've had similar issues, but I have a turbo. I've heard people having fueling issues that could cause this to happen, but the tech believes it could be derived from a bad solder on the ECU when it was taken out and appeared to have been reinstalled by the original car owner damaging it. They recommend a new ECU

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Quote: Me too. Anyone know what could cause this?

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Quote: What codes are showing? ECU=$$$. MAF cleaned/replaced? All brake lights work? Tire sizes with in spec front rear? AWD on Porsche can be very sensitive to front/rear dia differences.

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Quote: code is p0604 Internal Control Module Random Access Memory (RAM) Error and then a code for P1156 Manifold Absolute Pressure Sensor Open/Short to Ground. Tire size is stock.

Bad tune?

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Quote: Could be. I don't think the code 1156 is related, but 0604 appears to be. It was dyno tuned and done by a reputable shop. It seems as though at times the memory exceeds the capacity on the chip that the tune is saved and maybe that's what happens?

Have you posted this on Rennlist? The 996 turbo group is pretty active there. Also the 996 normally aspirated group has some good tech folks. You might get some good suggestions? https://rennlist.com/forums/996-turbo-forum-61/

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Quote: i had to endure this for 3 months and had changed the battery just on doubt. now it seems solved after a random try of pulling out the abs sensoer and cleaning the signal pick up area near the bearing generously with contact cleaner. finger crossed..

im in this pickle now. replaced the brake sensor first. nothing, replaced the battery....nothing. i get the abs/pcm lights when i hit 75mph. stopping and shutting the car off then restarting clears the lights and codes. im assuming for now its wheel speed sensors somewhere. will report back tomorrow once i run it thought tonight and throw the codes then out the reader on when codes are showing.