GG Allin

and no speedo. Is this a wheel sensor? Or something else? My mechanic's scan tool is in need of an update from Snap On, could not scan for drive train faults last night. Another mechanic friend of mine said it could be a "vehicle speed sensor" associated with the transmission output. Am I SOL w/out a scan tool?

ltc

Yes.

Your P!g can not determine individual wheel speeds, so independent ABS (software controlled proportioning/balancing) is no longer possible.

GG Allin

Got 'er scanned, what's all this about? ABS pump? Looks like it might be time to take it to the dealer and use the warranty.

mudman2

how old is your battery ?

ltc

Kind of a long shot, but worth a try...

GG Allin

How would an old battery trip a ABS sensor? It only happens when the car is driving, assuming that would be under the power provided by the alternator. They say the short term for all those codes is "ABS Pump".

deilenberger

On most modern vehicles - the modules have a shutdown voltage, when the voltage drops below a certain point, the module shuts down and records a fault. This can happen with an old battery during starting the engine. The faults often are for something not at all related to the low voltage condition.

On modern BMWs all sorts of interesting and exciting things happen (dashes go crazy, faults galore, windows going up/down by themselves..)

mudman2

Especially when so many things pop up at once

deilenberger

Yup. From what I can read on the estimate - it looks like communications problems.. which can be caused by a low voltage condition.

Just a FWIW - although the Cayenne is good about faults (hasn't tossed any - yet..) my BMWs love to throw spurious codes if they feel neglected. Before even thinking about "fixing" anything I reset all the codes (after noting them) and see if they reoccur. They very rarely do. The BMW scan tool I use (AutoEnginuity) also tells you how often the codes occured and if the faults are presently being detected. That info is also very useful for troubleshooting.

A failing coil will show repeated stored codes for misfiring, while one that was just not firing for a low voltage reason usually only shows one or two incidents. One is really indicating a problem - the other is a wild goose chase up a blind alley.

I'll just add - this is when a really good mechanic is worth their weight in gold vs one who just blindly swaps modules/parts based on what his scanner is telling him.

Another FWIW - if all he has to use is the SnapOn scanner - it isn't terribly good according to my mechanic. It misses some things and misidentifies others. A dedicated Porsche scan tool (Durametric comes to mind) is likely to be much more accurate.