2008 S80 V8 Charging system failure

warcraftjunkie · Post by **warcraftjunkie** » 26 Jun 2015, 15:12

So for the last couple days when driving home I've been getting the big red warning about charging system failure. It normally comes on about 3 minutes after I start my drive home, and is on for about 5 minutes then goes away.

Well, this morning I was heading to work and the light came on about 10 minutes into my drive. At a stop light it was idling just fine, but when the light went green and I gave it gas to go... it just rolled forward with no additional throttle.... then all kinds of other warning lights came on regarding all the controls. I was able to get it towed home and tested the battery level. It was running about 7.8v. So, I gave it a jump from my son's car and drove it around the block with no warning lights. Pulled it into the garage and tested the battery (post to post) and was getting 12.3v with the car off, and 14.3 with the car at 2000rpm. Disconnected the battery and put it on my charger and noticed there's quite a bit of corrosion on the negative battery cable. I know these V8 Models have issues with the alternators, but do you think my problem could just be simply the negative cable not maintaining a good ground?

warcraftjunkie · Post by **warcraftjunkie** » 26 Jun 2015, 15:47

Peeled back the sheath on the negative cable...

warcraftjunkie · Post by **warcraftjunkie** » 26 Jun 2015, 17:37

So, I went to the local autoparts store and bought a negative battery cable. Mounted it up, and slathered the ends in the terminal grease and took it for a drive. After about 5 minutes of driving...the alert returned. I drove home and while the alert was still on, I measured between the posts and it was 11.28 and dropping (car was running at idle with accessories on). I went and sat in the car and waited while it was running. Eventually after another 5 minutes the alert went off and I again measured between the posts and I was getting around 14.3v. Soooo, faulty voltage regulator? I hear that the voltage regulator on this model year is internal to the ECM, that true?

Post by **jimmy57** » 27 Jun 2015, 01:19

The voltage regulator (AKA alternator control module) is internal to alternator. The engine control module can adjust charge voltage level.

warcraftjunkie · Post by **warcraftjunkie** » 28 Jun 2015, 17:52

Took it back to the autoparts store after putting the battery on a trickle charger over night. At first it passed battery, alternator, voltage regulator tests. I drove it around the block for about 5 minutes and like clockwork the alert showed. I immediately drove it back and had them test it again, this time the voltage regulator failed, but alternator was listed as passing.

warcraftjunkie · Post by **warcraftjunkie** » 28 Jun 2015, 18:20

Hmmm, why is it that a voltage regulator by itself is more expensive than an alternator with the regulator on it?

https://www.fcpeuro.com/products/volvo- ... 0-30667453 - 236.99
vs
https://www.fcpeuro.com/products/volvo- ... v8-al0821x - 231.99

I guess because the regulator is new and the alternator is a rebuilt with a reconditioned regulator?

warcraftjunkie · Post by **warcraftjunkie** » 29 Jun 2015, 13:44

Hey Jimmy, do you know if the procedure for changing the alternator on the S80 is the same as the XC90 V8? I see tons of documentation on the XC90, but nothing for the S80. Seeing that they have the engine in the same orientation I'm assuming its going to be the same process of removing the RH Axle and all that fun stuff.

Post by **jimmy57** » 29 Jun 2015, 21:55

Yes, it is much the same as XC90 V8.

The reman'd alternator is from Bosch and the VR is from Volvo.

Since the ECM "talks" to the VR about charge rate and some diagnostics I'm not too hopefull that a VR is avalble from anyone else unless Bosch offers it.

warcraftjunkie · Post by **warcraftjunkie** » 01 Jul 2015, 18:14

Found a genuine new Bosch Voltage regulator at several online parts departments for dealers around the country, but then found a seller on Ebay selling the identical Bosch part for half the price. I'm naturally wary of things that are half the price of what others are selling it for, but thought I'd give it a go... should be here on Thursday or Friday so I'll report back after the weekend.

warcraftjunkie · Post by **warcraftjunkie** » 18 Jul 2015, 13:56

So, is there a magic trick to getting the passenger side axle out of the hub? I've disconnected the Outer Tie Rod, the Sway bar end link and have rotated the hub assembly hard left. I've unscrewed the axle retaining bolt and pushed it the axle back from the hub assembly as far as I can, but its still not quite far enough. I've tried jacking up the hub assembly and tried from several different angles and still can't quite get it. I don't want to undo the lower control arm connection to the wheel assembly if I don't have to, but I'm getting to that point I think.

I've seen other tutorials for the XC90 on this same issue, but I'm stuck... any advice?