So I just purchased an 05 2.4i, and off and on the Power system service urgent message lights up on my dash. There's no dimming of my lights or slowing of the fan blower motor when it happens, and there's no change of how the car runs or drives. Where should I start troubleshooting this problem?

 

start by putting a voltage meter on the car. Battery should be 12.6V with engine off. See what the altnerator puts out at idle and under full electric load (lights on, blower motor on full, rear defog on etc). Next is to inspect all cables - battery posts, ground strap etc - look for corrosion, bubbles in insulation etc. Its likely when the warning light comes on the alternator is not producing any volts and you're running off the battery only. This can be due to a bad voltage regulator or an issue with the voltage sensing for the alternator.

 

Well I checked the voltages, with the car off the battery is at 12.6. Car on, it's 14.5 running normally and 13.4 with all accessories on. The power system service urgent message is on when the voltage reads 13.4.

 

sounds like it may be sensing too much resistance in the cables. See if cleaning and tightening the battery posts helps. I also wonder if there's something going on inside the battery - is it old or did the problem start with a recent battery change?

 

The car was just bought last week. The battery doesn't look to be that old but looks may be deceiving. I'll try wire brushing the battery posts and terminals first and see if that helps at all and if not I'll have the battery tested. I'd rather exhaust all my other options before I look into a new alternator or something of the sort

 

I clean the batter terminals and connections. Still getting the same thing.

 

You might be able to get that alternator checked for free at an auto parts store (some will do things like that). I can believe that's where the problem is, since it appears that the alternator isn't up to the full load.

 

My first V50 did exactly this just before the alternator died. My present V50, the alternator just died without warning.

 

Ok. Anything I should know when getting a new alternator? Just wondering since the ECU controls the voltage regulator.

 

Did you get a new alternator? When mine started with the error message I replaced the alternator with a reman unit from one of the chain auto parts stores. The first one lasted for a couple of years. The second one lasted about a week. The third replacement was from Amazon and was listed as new. It was not a new one but it looked 5X better than the chain store versions. This one has lasted over a year so far.

After I got the car back on the road I took the original Volvo unit to a local rebuilder. He ordered good quality internal parts and rebuilt it. I know have a spare for when the current unit fails. If you have time and a local source then I would recommend getting yours rebuilt. It's still cheaper than the reman units.