fstede1

PSM Off ABS Failure warning flashed today. Turned motor off then back on no warning. Showed a second time after car was restared and driven say 10 miles. Will be heading to see Tony at Calles Rennsport but in the mean time what is this all about?
Thanks

Letmebegus

Bad alternator putting out low voltage caused those readings for mine. Tech said low voltage causes all kinds of weird readings on the sensors. That is one possibility.

dantzig

There are dozens of possible causes of the PSM/ABS failure lights. Any set of conditions that makes the ECU think that the sensor readings it is seeing are inconsistent will trigger this pair to come on, as the ECU says, "I'm not sure what's going on, so I am not going to intervene with PSM or ABS." Here is a short list of documented causes that I have seen over the years:

Bad MAF (most common cause)
Steering angle position sensor value wrong
Failure in ABS module
Failure of wheel speed sensor
Alternator problem as noted by Letmebegus

The first thing to do is to get the codes read. That usually narrows it down pretty quickly. Do let us know what it turns out to be. My guess is MAF., since that is the most common cause.

Jon

fstede1

Thanks for feedback. TT to shop next week. Will keep you posted.

SSST

x2 on the low voltage. Bad battery caused all kinds of weird stuff.

Mikelly

If you don't want to be totally dependent on the local shop, do yourself a favor and buy a durametric code scanner and clear the codes yourself... Also, here and download the factory service manual so you can understand more about the codes, and your 996TT: http://locodemoto.com/tech/996turbo/996turbo.zip


Mike

Radio996

+1 for the MAF as likely cause. Do you have an "oiled" air filter?
It is easy to clean the MAF with electronics cleaner spray. Try it. you might save a trip to the shop and a few $$

Mikelly

Yea, careful with that whole "oiling" of the filter... And after talking to several tuners who've dyno'ed them, I moved back to the OEM filter because there wasn't any appreciable difference in power and an actual risk of letting more dirt in than the OEM filter... So it just wasn't worth the chance of ruining a MAFS or making more work than needed over NO gain in performance.

Mike

C5Driver951

I did the same as Mike. Tossed the "improved" filter in the trash. Too many MAF failures in these cars.

Oh and I had the same code when the MAF in my car failed. Oiled filter?

Carlo_Carrera

Thanks for the service manual.

nick49

This can and will happen if you fit tires that have a greater than recommended size differential between the front and rear diameters.

fstede1

Me with a manual, now thats pretty damm funny. I'm a bad *** when its detail time. Mechanial skills? Your talking to the wrong guy. I do have a K&N installed, maybe that is short lived. Turbo to shop next Thursday. Will keep you all posted.

dantzig

If the K&N is a recent addition, it could be the cause. Oil from the filter has been seen in many cases to collect on the MAF sensor. When the MAF stops working, the PSM/ABS fault lights appear.

You can try cleaning the MAF. There 's a DIY somewhere, but here's the quick version:
Remove electrical connector from MAF by squeezing and pulling up
Remove two "security torx" screws holding MAF in place
Remove MAF. Spray sensor with electronics part cleaner. The sensor id the brass colored tab at the bottom, not the resistor in the middle
When dry, replace and reverse the above steps.

Do try very hard not to drop the screws into the engine compartment.

If you just wait to go to the shop, and they replace your MAF, save the old one and clean it, just in case it turns out to be useful sometime.

Jon

fstede1

MAF was my problem RnR cost covered by my extended warrenty.

JG 996T

Just got these codes twenty miles after picking car up from new clutch install - wheel sensor? I'll read the codes in the meantime