# Can/Bus problem? Solution?



## Hasenpfefer (May 21, 2002)

Bought a 2005 Jetta TDI in Febreary. It had a lousy aftermarket radio. Bought an OEM radio online. Installed it. After a couple ofweeks my alarm started going off on yhr car every 15 minutes to half hour. Then the battery would drain overnight or within days. Took it to my shop in July and it is still there, Says it is a Can/Bus problem but having trouble figuring it out. This seems like a ridiculous problem and has really turned me off to VW. Isn't there a quick fix? Can't something be replaces or reprogrammed?


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## stratclub (Feb 3, 2007)

Bashing a technology because you don't understand it is certainly a poor way to deal with it. Just so you know , many new cars have CanBus. Did you buy the radio used? It could be that you bought a radio someone sold because it was defective and draining their battery. Drive around with it unplugged for a few days and see if your battery still goes flat.

OEM radios can work great until they don't. Some folks have had the same problem you describe with their OEM VW radio. First step, see if the radio is actually draining your battery. Oh and get your car out of that shop. They don't sound like they have a clue. Almost 3 months to identify a problem that should have been identified in about 2 hours or so? Amazing............

CanBus is actually pretty simple to troubleshoot if you understand it but it does work very differently than the analog dinosaur electrical systems on older non digital cars. https://www.youtube.com/watch?v=FqLDpHsxvf8

This VW TSB: http://pics.tdiclub.com/data/500/TSB_27_08_04_Matrix.pdf will tell you how to identify what controllers are not going into sleep state and draining your battery although you stated the problem didn't exist until you installed the radio. I would rule out or confirm your new radio is the problem by leaving it unplugged for a few days. Their is no magical reprogramming to fix your problem.


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## GTINC (Jan 28, 2005)

Hasenpfefer said:


> Bought a 2005 Jetta TDI in Febreary. It had a lousy aftermarket radio. Bought an OEM radio online. Installed it. After a couple ofweeks my alarm started going off on yhr car every 15 minutes to half hour. Then the battery would drain overnight or within days. Took it to my shop in July and it is still there, Says it is a Can/Bus problem but having trouble figuring it out. This seems like a ridiculous problem and has really turned me off to VW. Isn't there a quick fix? Can't something be replaces or reprogrammed?


These radio units have thief protection so that if removed from one vehicle, it can't be used in another vehicle without the VW dealer coding it to the new vehicle. You will need proof you bought the radio legally, not stolen.


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## Rockerchick (May 10, 2005)

Do you know if the car originally came with the Monsoon system? Could be the amp isn't turning off and draining the battery. Also, what radio did you get?


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