I have a 2004 grand prix with 126k miles on it and recently the charging system failure has come on the DIC along with check engine soon. I took it to both autozones, penzoil, and walmart plus a co worker of mine had done the test where you plug into the dash and no codes have been sent back. My co worker said that its giving diffrent voltage throughout everything and he dont know why. I have had the battery and alternator checked and both are good. Dont know what to do now please help?
on the DIC it says charging system failure, check engine soon, and sometimes when driving it says reduced engine power and its hard to turn when that happens and have to shut off open driver door and then restart to b able to drive it