I am working on the C5 I inherited from my cousin.... it is up and running after sitting for 8 years..... took off an old blower system and put back to naturally aspirated....... so some weird stuff...... when driving the car the dash is not lighted. I have tried turning up the lights on the dash but that does not do anything..... when I turn the key off the dash lights up until the timer shuts it off...... am I not switching something correctly.... start the car and the dash lights go out.... hard to see them even in the day with out being backlit.......

also..... when key is turned to the on position or the car is started it brings up Service Vehicle Soon in the DIC. Then it will bring up a charge system fault in the DIC..... the car runs good in town and out on the highway...... also the traction control and ABS lights are on.... the ABS module was out of the car when I took it under my wing for the rescue.....

When I pull the codes it gives me P1571, and a P1638.... my list says a P1571 reads as ASR Desired Torque..... no clue on that. It also lists a U1040 Loss of Communication with the TCS..... no clue on that one either....

The battery is brand new and charged up........ any help would be appreciated....... the car has been turned and a blade MAF from a C6 intake system has been wired in and tuned for the car.........

 

Not sure what is going on with the dash lights, but most of those codes are due to the lack of the ABS module. The charge system fault is nothing new. What I find is that if you turn the key to "on" then wait a sec or two before you actually start it I never see the charge system fault error. I tend to see it when I start the car right away.

 

ok thanks.... good info..... we put a real scanner on the car today and checked the grounds and did other checks and came to the same conclusion that it is the ABS module...... cleaned the plug to it and still no communication from the ABS......

the dash light thing is weird...... works when the headlamps are on....... but not just running in the daytime..... are they supposed to be on to backlight the gauge cluster.... my C6 was always lit.....

 

Moved to C5 Tech for more discussion.

 

I am 100% certain the dash lights/backlights do not illuminate unless the headlights are on.....