I can't unlock the door using the key or key fob nor start the car. This has been periodically happening for the last year or so. To fix it, I have to disconnect the battery cable and reattach it. The car will work fine for weeks or months at a time then it will occur again. Then it happens again and the only way to unlock the doors or start the car is to disconnect the battery cable again and reattach it.

My car is a 2004 S80 non turbo.

Any suggestions on how to find the issue?

 

I read a post on how to troubleshoot battery drain today. I am going to test the voltage to see what my normal current draw is. I hope this will help be diagnose my problem. I will post my finding afterwords.

 

My 2000 S80 also does that once in a while. Hell, it even goes completely dead when i least expect it, like doing 120 kms. on the highway !!! It wakes you up real quick.

Anyway, to eliminate the need to disconnect the battery every time that happens, I rerouted the positive cable that runs under the carpet on the driver's side through an on/off switch, and installed it on the plastic cover bellow the steering wheel. It does not look pretty (very Un-volvo like :-) ) but it saves me having to go into the trunk all the time. Just have to make sure it is a marine master switch or equivalent, able to handle the cranking amps put out when starting the car. Hope this helps .

Merry Christmas !!!!

Joe