blackultra

Spend countless hrs over the last 4 months trying to pinpoint CEL:P0501
Recommended and did changed both front abs/speed wheel sensors, problem still exsist. Speedometer is intermittent; sometimes it works,sometimes it doesn't. It mostly works after sitting overnight or for more than 3-4 hrs. CEL, ABS & ESP are illuminated when speedometer goes dead. Since it's a 3.0 Tiptronic so I was told, it doesn't have a dedicated tranny speed sensor. Overall it drives and runs fantastic with a little bit of brakes pedal shudder once a week or so. Could it be something to do with the ABS ?

Et Cetera

Sounds like it needs an ABS control module.

The speed signal is generated from the wheel speed sensors. The ABS module sends the information to relevant modules on the CAN bus. No communication with the ABS module means no speed signal for the cluster/ECM.

Check your fuses/connections related to the ABS module.

Do you have VagCom? See if you can communicate with the ABS module at all times. Do you ever randomly lose communication/can't connect with the ECM via your scan tool? If so unplug the ABS module and see if you can communicate afterwards.

Also, I know many are against it, but the dealer could probably tell you whats wrong for a nominal fee and end your 4 month headache.

Anyway, thats what my parts shotgun thinks.

blackultra

Thanks a million EC, I was thinking that it may be along those lines but as you mention I just might have to take it to the Sealer or I meant Dealer for a pinpoint diagnosis. I had an oppurtunity to purchase a VAG dirt cheap a few years now I wish I did.

blackultra

Thanks a million EC, I was thinking that it may be along those lines but as you mention I just might have to take it to the Stealer... oh I meant Dealer for a pinpoint diagnosis. I had an opportunity to purchase a VAG dirt cheap a few years now I wish I did.