XC 90 Help

[VolvoRuss]

I don’t know where to start. I love my 05 XC90 V8 with 198K. Power System Failure light comes on regularly along with the transmission service light, brake system failure light, ABS, battery and check engine light of course. Been a problem for a while along with other symptoms. New battery gets drained regularly. New alternator last week. Will take a jump, but won’t last long. When the radio and AC turn off while driving I know the power steering is next and those power and engine failure lights/issues are imminent. Those are my indicators to pull over, but if I turn Volvo off it won’t crank back up w/out a jump. If I continue driving the gas pedal will go to the floor and the car stops...Help

[matthew1]

Did you buy it recently? Did you run a Carfax on it? Was it a rebuilt or salvage title?

[SuperHerman]

It sounds like you have a parasitic drain (short) somewhere. There are multiple videos on the subject on how to find the offending circuit.

First you have to eliminate the alternator, although if you had the problem before and the new alternator didn't fix the issue it points to another problem. Would not hurt to check all your large gauge ground and power wiring.

Basically you get a VOM - set it to the amp reading - and start pulling fuses until you see a huge drop in load. From there report back or pull up the wiring diagram and chase down the short.

Until you find your short - you can not diagnosis any of the other issues - as they may be power related and actually not an issue.

Your problem could be a chaffed wire grounding out and only needing a little love - then again it could be serious. No way to tell without first going through the process.

[oragex]

As above. Something is not charging the battery - and perhaps also not giving the car enough power. The alternator it's an easy check, may even grab one of those chinese voltage meters that plug into the cigarette socket - will give you real time voltage which should be sitting around 14.4V when the battery is not fully charged

Look first at all power cables around the engine, fuse panels, battery, alternator, etc. Check also all ground cables on the side of the engine bay and also around the engine - may have a small cable behind the engine somewhere

Would also double check you got the right alternator and regulator for your engine

https://www.fcpeuro.com/products/volvo- ... 91#fitment
https://www.volvooftorontoparts.ca/p/Vo ... gLfF_D_BwE

[VolvoRuss]

It’s a family hand me down with every service on file until me - 8 years running. I keep thinking about CEM ECM issues but don’t even know what those acronyms are. There was once a problematic headlamp that mysteriously got resolved with a new battery (previous battery was incorrectly purchased/installed, that is the wrong suggested battery). I do see previous rodent activity in the form of shredded fiber from a barrier between the engine compartment and the cabin... so I will start checking fuses as discussed above.

[ggleavitt]

This is a 2005 so has the older version plenum cover over the CEM (Central Electronic Module). Would not hurt to pop the hood and shine a light down through the windshield drain screen on the driver side and see if you've ever had any significant water ingress and/or the bottom drain is clogged. Check the passenger side as well (since you're there). Drains may be cleaned from under the car if needed- rubber duct each side of the rear engine bay, with a flap on the bottom, do NOT have your face under the drain when you move the flap.

Might be also be good to get under the dash on the drivers side and remove the bottom cover, look closely at the large electronic module above the brake pedal area (that's the CEM) for corrosion or staining or any evidence of water coming in from the top.

Your approach is sound, just wanted to add the drains and possible water ingress to the mix.

See http://xemodex.com/blog/volvo-central-e ... -xc70-xc90 for a visual, vehicle in the video has the newer cover.

edit 090519- typo