My '02 C4S had the ABS/PSM failure warning come on a few times last year. I read the forums and tried the simplest fix first ... brake pedal switch. I cleaned and re-lubed the contacts with dielectric grease, pulled the plunger fully out to reset it, and installed it again. No problems after a few weeks and then same thing again. Used Durametric to clear the ABS/PSM pressure sensor code. Awhile later, I have a check engine code come up that my bank 2 catalytic converter had an issue??? I cleared the code and it was off for a longer period.

I have since begun driving the car now that winter is over and catalytic converter code has come back. As well, the ABS/PSM failure has occurred when driving the car in the morning (temp. outside is 12C). After about 30 minutes of driving it finally doesn't come back on until the next morning. Each time I shut the car off the ABS/PSM clears itself, but the check engine for the cat.'s remains. ABS/PSM shows pressure sensor code, but my brake lights function properly. The ABS/PSM failure occurs while driving (low city speeds) and not when the brakes are applied (last season the code came up when brakes were applied, but I cleaned the switch as mentioned above).

I have a stock paper air filter. Fresh tank of gas and oil change. Problem persists ... I told the P-dealer I will bring the car in because I think my catalytic converter is faulty and it's under warranty for the few months remaining. However, it might show a code for the catalytic converter, but could it be something else instead??? I don't want to get dinged for a $132 diagnostic charge when I have my own Durametric to show the same code.

How do you clean a MAF sensor and with what chemical? I have read so many options of diagnoses on here and I don't have any idea what it could be.

Any input is appreciated. Also, if there are any Porsche tech's in the Toronto to Niagara region I would appreciate it if you do service on the side.

Thanks

 

Mine was a bad cat and they replaced it. Lucky I had a couple months under warranty cuz it saved me like $1400. Its well worth the diagnostic fee as I've also tried resetting codes only for them to eventually come back.

The last ABS/PSM fail code came up couple months ago and was reset by dealer, they weren't sure why it even came up, said maybe attributed to dirty air filter and MAF sensor. Hasn't come up since.

 

Thanks for the info. I will have my service appointment, hopefully it is just the cat. and they replace it under warranty. If it still persists, then I will change the brake switch. Does anyone know how to clean the MAF sensor and with what?

 

mine was bad clock spring - the air bag contact in the steering wheel. if you notice that there is a white dust on top of your steering column, that may be it. error codes are the key.

jb

 

Buy a new MAF sensor. Mine keeps lighting up no matter how I cleaned it.

http://www.autohausaz.com/search/pro...0Mass%20Sensor

 

Wow, thats a great price!

 

I had an identical issue with my 02 c4s. I did a lot of what you mentioned above and it turned out that a good clean of the maf fixed the issue. I went to the local parts store and they had maf cleaner .. I cleaned it twice .. 1k miles later still no cel abs failure lights