In the dash or somewhere else? Is it the kind that uses a cartridge?
The dash units are high failure items with a lot of plastic parts that break. Some failures are with the microprocessor but most are mechanical in nature. When the microprocessor develops a problem with the "reset" circuit, it doesn't show up until the battery is disconnected or run dead. It's similar to the boot up sequence of your computer. The reset circuit is not like you would think of resetting a circuit breaker. Its purpose is to set the millions of transistors inside the microprocessor to their starting point rather than at some random condition. The process takes a tiny fraction of a second, then it's over with until the next time memory power is removed. Problems related to the reset circuit are somewhat common but don't show up until the battery has to be disconnected for other service. A lot of mechanics get blamed for causing the problem when in reality, the real problem occurred months or even years earlier.
If you have the remote changer that uses a cartridge, the mechanism will cycle through the trays to relearn which ones are empty and which ones have a disc in them, but it might not unload the last disc back into the cartridge first. That means it will try to load a disc when there is already one in there. To remedy that, pop the cartridge out, remove all of the discs, and reinsert the cartridge and let it cycle through all of the trays. I have to do that three or four times with mine before it will unload that disc, usually number two, then I can reload all six and it will work fine. That car sits in storage most of the time with the battery disconnected. I've learned that to prevent the problem, I just remove the cartridge before unplugging the battery cable.
Thursday, July 15th, 2010 AT 1:48 PM