2009 Audi A4 2.0 battery drain
The battery drain drops to near 0A when the Data Bus On Board Diagnostic Interface module is disconnected. I tried a used module but the drain is still there and then the customer needed the car back quickly, so I couldn't pull the codes.
Does anyone know why that module is not going to sleep?
A codescan might give u a clue on what’s draining the battery. but you should identify what data line is staying up hook up your scope to see who is not going to sleep
Probably not a comfy pillow. Data line can't sleep. Suggest counting sheeps
Thanks Eri, I'll do that.
There is an input causing the module to stay active.
Thanks, i'll scope the wires at the module to see which CAN wires are toggling
First thing I'd do is check for codes, check for tsb, check module inputs
Thanks Mario, I'll do that
Hi Ray, along with what others said, here is one more consideration: while checking the codes look out for a CAN bus being in the one-wire mode. That Data bus module is a gateway for several CAN buses, some of them Low-Speed. The gateway will not go to sleep if an LS-CAN is in the one-wire mode. This can be caused by a wiring issue (for example, break in the door harness), or by one of the
Wow Dmitriy, good info!
The peaks of your scope pattern are 1.6 amps, but the valleys are 0.0 amps. The duty cycle of the pattern is approximately 50%, so you could guess that the average draw is about 0.8 amps. Also, you could try using the Measurement menu or a Math channel to get the average. At any rate, 0.8 amps is still too much. Have you found any documentation for how long you have to wait for the car to go to
The amp ramps looks like the module is being turned on and off? I found one document that says to wait 2 hours for the modules to go to sleep. Thanks Steven
Any evidence of water intrusion ....modules in the floor? Codes would helpful
The car is in a body shop right now for some minor damage and when I get called back in to the shop, I'll ck codes in all modules.
The first capture and the PSD file, is from the used Data Bus On Board Diagnostic Interface module J533 with the key off and the module should be sleeping. The module is slowly drawing from 0A to 1.5A, then the amps slowly go back down to 0A. The original module has the same slow on off current ramps. When the module turns on and off, the current draw should be a square wave. Any thoughts? The
All this is really good, but a complete vehicle scan need to be done before pulling the scope out. all the modules report to the gateway. we need to see if there are ANY codes. Dmitry is correct, if there are any codes for the data bus being in single wire mode, the vehicle may have issues going to sleep. Post the results of your code scan here.