Alternator Issue?

pjohnson · Post by **pjohnson** » 22 Feb 2010, 18:38

Quick question for the forum ---

Driving home tonight, my 2003 XC90 (79k miles) lost power on the highway. I pulled over to the shoulder and put it in park and got a message that said something to the effect of 'diminished engine quality'. I really can't remember, as my attention was more on the traffic speeding inches from my wing mirror. The engine was still running, no strange noises, but very weak. Would barely rev, low RPMs. I saw no other blazing 'error' lights on the dash. When I turned it off, I noticed the hazards were barely bright enough to see. I'm thinking alternator. I called the tow truck, blah blah blah and in the meantime tried to restart the car. Started right on up, lights were bright again and all was fine. No 'messages' in the little message thingy except that I need to fill up my washer fluid. I moved further off the road and waited for my tow.

I think it's clearly something electrical but want to know enough to be prepared when the mechanic calls tomorrow with the prognosis. Any ideas? THANK YOU!

Post by **OEMVolvoParts** » 23 Feb 2010, 11:46

I don't want to jinx it, but I doubt they will be able to duplicate your issue. Sounds pretty random. I'd start with a new battery just to rule that out as causing problems. Low voltage batteries will cause the electronics to do strange gremlin things at times. From there it gets worse and were only guessing, so lets start with the battery and hope all is ok.

pjohnson · Post by **pjohnson** » 23 Feb 2010, 13:45

I'm hoping it's something so simple! Thanks for your reply. I'll post an update soon.

-Paige

pjohnson · Post by **pjohnson** » 23 Feb 2010, 19:11

UPDATE -- I've been told the issue is either a throttle unit or electrical harness. According to him, the electrical harness can't be ruled out until the throttle unit is replaced, so they can get a clear read on the computer. So it's a $1000 repair before they can even confirm I may/may not need an additional $1200 electrical harness.

When I asked why the hazards/lights would dim, indicating it may be something electrical, I was told if the throttle unit is malfunctioning it can 'pull a lot of juice' and give the impression it's an electrical problem. The computer did not get a message indicating an electrical issue.

I'm not doubting the somewhat vague prognosis but am skeptical. And bummed. If anyone out there has an opinion on this, I'd welcome your thoughts.

Many thanks --

Paige