View Full Version : Car Problems

01-15-2007, 08:51 AM
So the "check engine" light popped on a couple days ago, and this morning I find my battery dead - any possibility these two problems could be connected? I'm ordering a VAG COM cable today to find out about the light, but perhaps someone more knowledgeable would know why these two things might have happened? [confused]

01-15-2007, 10:53 AM
It's very hard to say whether the two issues are directly related. You may have had a weak alternator which lead to the dead battery. There is a low voltage CEL when the battery is diconnected and then reconnected. Perhaps your battery was so low on power that this type of condition was experienced by the ECU. I'd get the battery on a trickle charger and let it run over night (without the car's battery cables connected). After it has charged, let it sit for two hours and then check hte battery voltage with a multimeter. If voltage is high enough, proceed with connecting it back to the car. If it's still low after a trickle charge and a two hour rest, you will need a new battery. The two hour rest is recommended in the Bentley manual to ensure that the battery is in a "resting" state before you read it's voltage. Testing it right after charging it can give a false positive.

After you've got your battery issue corrected, you can start your VAG-COM checks.

01-15-2007, 11:42 AM
Thanks for the info - I finally got a friend to give me a jump, but the engine will still not start (the starter goes . . . but no boom boom [=(] ). I checked all the fuses and they all look good.

Any ideas/input welcome!

01-15-2007, 11:57 AM
Don't bother trying to jump it. Your battery is wiped out. Charge the battery first and start fresh.

Jumping the car to a start on a dead battery is going to force the alternator into overdrive. It will run as hard as it can to get the battery back to full power ASAP. You're better off charging and giveing the alternator a break. Plus, if the alternator is toast, it won't charge the battery and you won't have enough voltage to run the coils.