Hello everyone

Newbie here to the forums. My wife and I just took over our parents 2004 XC90. Love it! A week after of having it, we ran into a problem.

When I start it up, it starts up normal then all the lights on mph etc... dash goes out and all of the needles drops to like it would be if the the car was turned off.

When I press on the gas pedal, it takes quite a bit of pressing on the pedal to get it to go. Towed it to Volvo this morning and they told us its something with the ECU. They had reset the ECU and the car is working fine now. They don't know what caused it to do what it did and isn't sure if it would happen again. To replace the ECU, it is going to cost $1,100.00.

My biggest concern is it going to happened again while my wife with our 2 kids are in the car in the FL heat.

If I can get some feedback as to if I should replace the ECU or could it be something else.

Thank you in advance for any feedback.
TTran

 

I would wait and see if it happens again. I have not seen the modules fail in an XC90 as of yet.
Maybe it was just a fluke.

 

I have had an ECU failure on a 2006 XC90. It was 1 month short of 3 years old and the engine just stopped (at night), with no power steering, no nothing. Had to coast to safe place. It did not cause any other damage, just the inconvenience of having to have the vehicle recovered. That was another story: the local dealer had closed down, so rang nearest dealer next morning (40 miles away) they arranged for recovery and said it would be covered by warranty. When I collected car a week later, ECU was replaced under warranty but dealer would not let me have the car back until I paid the recovery costs.

Never had another Volvo - but I miss it.

 

This is a very common problem with the XC90, if you do a google search on "xc90 turned off while driving" you'll find lots of information regarding this issue.

The problem seems to be build quality of the xc90, the sun roof leaks causing the floor boards to flood out, easy fix but hard to tell when it's not working correctly. The ecu is under a seal that goes bad and allows water to leak onto it (dealer acknowledged this as a known issue). I'm currently going though the same problem and have stopped by the local dealer to see if they can goodwill anything, honestly it should be a class action law suit, they knowning know of this problem and it relates directly to there poor build quality, why do I need to pay for there known mistakes??

I've talked to the dealer who was suppose to get back to me today, but didn't, about installing a used ecu. The dealer surprising doesn't want to do this but wants to charge me the $1000 for a new one, used unit is around $100 from www.car-parts.com. The dealer claim is the used unit could fail and the repair will have to repeated down the road, I however feel that it's my money and I should be able make that decision on my own.

************************************************** **
In most or all of the above cases above the problem will be the CEM.
The CEM is located under the dashboard above the drivers feet. On early XC90 and some XC70's there is a service bulletin related to water migration from the base of the windshield through a now redesigned wiring plenum. It is positioned directly over top of the CEM. Later models of XC's all have the updated plenum and therefore no water leakage on to the top of the CEM.
The original CEM circuitry has not been conformally coated to prevent water damage to the CEM, and so after the water has leaked through the vent holes in the CEM and caused corrosive damage to the board, the car starts to misbehave.

Xc90 Electrical/engine Power Failure - Volvo Forum : Volvo Forums

Volvo XC90 reportedly under NHTSA investigation for intermittent lighting failures — Autoblog

2004-'05 Volvo XC90 Checked for Electronics Flaws, Says NHTSA

Not related but...interesting stuff non the less
Volvo Cars Class Action Lawsuit Filed Over 2004 Volvo XC 90 Transmission | ClassActionLawsuitsInTheNews

Volvo XC90 Transmission Class Action Litigation | Chimicles & Tikellis LLP - Class Action Law

Sunroof class action?? This should have addressed by volvo, simple fix and its the right thing to do and good PR, wonder what ever happened to this one?

Volvo XC90 roof leak class action lawsuit? (Volvo XC90 Auto Body)

 

Similar issue except, 2004 XC90, turbo. We can go about 3 hours continuous driving then all the gages go out and we have to sit somewhere with the hood up for about 30 minutes before we can go again. Then, about 20 minutes before we have to repeat this process.

I'm guessing I need a new ECM. If I get one from a similar vehicle. Year and model, would I need to get it programmed or 'flashed' to my specific vehicle for it to work or could I simply replace it with the similar model ECM and not need programming? After some research it seems the same ECM would work for a few years and models so hopefully no programming?

Anyone out there know either way for sure or know where I could look?

Thanks!

 

my 2005 xc90 T6 does the same thing while driving down the road the instrument panel goes dead, after a while it comes back on, motor never dies going down the road