2002 2.9 electrical issues.
 

Hello everyone. I picked up a 2002 S80 2.9 for a daily driver. The car is bone stock except for a HID lighting system I installed. I have NO engine codes. My scanner reveals "No Codes". I get 4 messages on the dash
1.Low beam failure (Started with the light upgrade)
2. SRS air bag service required
3. Alarm system service required
4. Electrical System service required.

#4 started yesterday along with a battery light. I have had both the Alternator and Battery tested. Both check out perfect. I have been driving for 2 days with the battery light lit. Car behaves and drives normal. Only behavior issue #4 has brought is on initial startup the interior lights flicker. Once I rev it to 4grand

Your scanner is generic and can't read SRS codes or codes in other modules, like the UEM for the bad siren causing the alarm message.

Electrical System Service Required is tied to the battery light and is a bad alternator. Never seen it come on with a good alternator.

Alarm system probably means the dreaded alarm batteries have leaked onto the motherboard and killed the alarm. More details here: http://www.matthewsvolvosite.com/for...p?f=11&t=17479

Not such a hard job - just a bit involved. New alarms are around $80 and up if you check ebay. I would always buy new as this problem is a design fault :confused: and will be in all used ones! :eek:

I had the same thing happen to me in a truck I own. It was the alternator. It would have issues until I reved up past 4000 rpms and then happen as soon as I stopped and restarted the truck. I had the alternator tested 3 times and it passed every time. I just replaced it and haven't had a problem since.

Thanks for the help guys. I replaced the voltage regulator and all charging issues are fixed. FYI this job can be done without removing the alternator. Took about 30 minutes and cost me $37 on ebay