4 replies to this topic

[flaco]

So I heard a faint 'whine' the other day in the garage, thought it was the neighbours... not.

Morning after, the garage had HEAVY gas fumes... scary! I had just filled the tank, so I didn't think much about it. Prob overfilled the tank.

That night, the whine was there, and morning after there were gas fumes. That night I decided to hear closely, and it was coming from the gas tank! Pulled the fuel pump fuse (engine fusebox) and whine was gone... WTF.

Reading through vida I found the pump is controlled by no less than 3 computers... the engine module tells the fuel pump module what pressure is required. The engine module also tells the central computer CEM to turn on/off power to the pump & pump module. I dissasembled the CEM tonight, and found the typical relays that eventually fail due to sticky contacts. While playing with the boards I noticed the contacts had opened, so back into the car it went... Problem solved - for now.

I was able to find the exact relays online so I ordered two and will be replacing them in the following days. What's scary is that I found evidence of water corrosion in the top CEM board. Water seems to drip from the wipers compartment right on top of the CEM, although no visible water traces were found. I don't see any other way for water to get in there, so I'll be using some RTV as well, after I replace the relays and assemble everything back together. The sunroof drains were cleaned about a month ago (they were pretty much clean anyway, only some minor crud in there).

The CEM is ~$600 from tasca, and it REQUIRES a dealer to reprogram everything (CEM has the car's VIN, inmobilizer codes, etc, etc) so don't even want to think how much they'll want for the job.

I've had the xc90 for a little over 3 months now, and it's a nice car, but seems electronics are the weak spot...

Seems fuel pumps are also a weak link... Could it be that the CEM is the actual culprit for keeping it running 24/7? BTW only the 'primer' pump was running, as the 'main' pump is controlled by the pump computer...

I'm thinking the gas smell means some sort of leak is present, although I can see how keeping the priming pump running could force gas past the pump gasket.... Before this occurence, no gas smells have ever been present in the car. No gas spots were found in the garage floor / under the car.

[831t5r]

Its actually pretty common for water to leak into the cowl.damaging the cem and/or engine wiring harness. I dont know how your service history is with your dealer but id take it in and ask for goodwill warranty for water leak issue. Our dealer has done it a lot

[flaco]

Yep, google shows some pictures of damaged units... The local dealer doesn't take volvos anymore, they used to be a ford/lincoln/mercury/volvo dealer and now they are ford only...

Besides, I got the car 3 months ago, so I'm pretty sure I'm on my own. From what I've read, dealers may or may not pay the bill (car is under 80k miles), but the software reinstall/upgrade is on my tab. So far, repairing it myself will be cheaper ($20 for 2 relays and $80 for a decent soldering iron). Planning to seal the wiring box with rtv and hopefully it will become leak-proof. Seems the 'official' fix was to replace the engine wiring harness and the box. I wish I could go that way but rtv is just cheaper lol...

Wonder where the water comes from... Is it the seal between car/wiring box/box lid or is it actually entering between the harness wires hmmm....

[831t5r]

I havent done one but i believe they enter through the cowl and the seal around the cem under the cowl

[matt b]

Can you post pictures ? I'm sure it would help others too. My XC90 is in a covered garage and parked inside at night but I'd still like to check it.