I have a 2006 XC90 with just over 100k miles. Wife was driving last week and it started “acting funny”, warning lights came on, and it wouldn’t start on the first crank. She got it started and got it home, but now it won’t start at all.

Background: Sunroof drain got clogged and hurricane Ida dumped a ton of rain, resulting in wet floors. Problem started several days later. I subsequently pulled the carpets out of the front seats, and sucked about 6 gallons of water out of the vehicle. Stereo amp did not appear to have gotten wet. Wiring harness (4 wires) under carpet drivers side was corroded, so I replaced it.

One more strange symptom, when the key is in the ignition, there’s a repeating three clicks (like O in Morse code) from under the center console. When I put my foot on the break, it stops, then returns when I remove my foot.

Messages: “Brake failure”, “airbags failed”, “immobilizer see manual”. CEL is on, along with ABS light and battery light.

What I’ve done: tried resetting ECM with the “lock/unlock 5 times, turn key 5 times” thing. Still immobilized. Tested and charged battery, and tried to swap the battery out of my other car. Nothing. If I turn the key and try to start it quickly, it’ll start for a second or two before the immobilizer kicks in.

I pulled the CEM, which was a little dusty, but showed no signs of water/corrosion on any of the connections or circuit board. I reseated all connections, and still have the same problem. I do the “reset on/off 5 times” thing between each newly attempted fix. I only have 1 key, so I can’t check if it’s the key, unless there’s a method I haven’t heard about.

Also, I only have a basic Bluetooth OBD2 scanner, which doesn’t work when the car isn’t running, so I can’t pull codes. I really don’t want to tow it to a Volvo dealer, because the nearest one is 50 miles away. I would be open to buying a good scanner that will work when the car isn’t running, if you have any suggestions.

Where should I go next?! I’m stumped. We just got the car a few weeks ago, and it’s been great until this. We spent our entire car budget on it, so getting rid of it and moving on is not an option.

Thanks for any suggestions.

 

Unfortunately your next step will be to scan the car with a compatible scanner. You or someone else. The best is VIDA. You can find the stolen/hacked version of 2014d free on the internet. Or there are others who sell for a reasonable price copies on a thumb drive. You will need a DICE unit to interface with the car. I paid $85 for a working clone DICE a few years ago ( The first one I received did not work) And VIDA works without the car running.

Xemodex gives this text for common failures of the CEM

Common Failure Symptoms

▼Common Failures:
• Water damage
• Complete loss of communication where the CEM will not communication with the rest of the network and the diagnostic tool.
• No LIN communication with alternator (ACM)
• Starter motor not working even though start is approved by the immobilizer sequence.
• Turn signals not working are all or one side turned on continuously.
• Low beams, high beams or fog lights failures.
• Horn not working at all.
• Wipers not working at all or stuck in high speed.
• Fuel pump not engaging.

Common Immobilizer Failures:
In order for us to properly diagnose any immobilizer failures you would need to send us your CEM, ECM, and at least one key.
If VIDA diagnostic tool shows zero keys stored, the CEM has lost it’s key programming. This is due to a faulty CEM. If you’re able to program keys into it again, chances are it won’t last long. To fully rectify the problem, we’d need to perform a CEM program transfer and then reload the keys. Additional costs may apply.


You removed and inspected the CEM? This part?

 

Thanks for the reply. Yes, that’s the part I pulled and checked. I’ll see about getting a scanner like you’ve described. I’m now leaning towards a bad CEM because the on-dash errors keep changing (now it says transmission service, even though the car hasn’t moved in a few days). If it’s a bad CEM, would the scan show that, or would it show up as other errors (ABS, airbags, etc) due to the bad CEM? Would either of these work with VIDA?

 

Your first picture is a clone DICE unit with a hacked copy of VIDA 2014d. Hacked to run without purchasing a subscription. You will need a Win7 pro Cpu w/minimum 3 gb Ram to install VIDA on. And it is most compatible with IE9. Most people have a dedicated laptop or desktop to just run VIDA.

Others have gotten Vida to run with 8 or 10 - or sell a bootable flash drive.

I have no experience with the icarsoft scanner - will it talk to all 20 of so modules? including the CEM?

Vida will be the best choice - it is the factory software/diagnostics/parts catalog/service procedures/specs and wiring diagrams if complete. Everything you need is on 2 DVDs.

Vida also gives possible causes and solutions for codes (that a normal scanner does not). For instance you have a ecm code 330b - volvo gives this information when you click on the code, with links in blue to other parts of the program (in this case specs, wiring, replacement procedures and other stuff) All that info helps you diagnose the problem not just guess and replace parts until it might be fixed. Vida will not tell you the CEM is bad - you eliminate all the other possibilities first before condemning a CEM. But given your car flooded and water intrusion is a known problem/CEM killer on some xc90s - you easily could be needing a replacement. Check xemodex.com - I've used them for hundreds of control units over the years with a 99.9% success rate. Be sure to find the updated service info to reseal the CEM cavity when it goes back together. That will not be in VIDA - for that info came out after 2014

 

Thanks for all the suggestions. I bought a Dice/VITA combo on Ebay, got it all set up and going on a laptop about two hours ago.

I connected it to the XC90 and… nothing. It wouldn’t even connect. Said it might be a CEM/ECM connection issue. Dejected, I pulled the CEM again and reinspected the connections. I hadn’t noticed it last time, but one of the pins in one of the connectors was bent and touching another pin! I carefully straightened it out, reinstalled the CEM, and it started up! VIDA connected perfectly, and showed me a ton of codes. I cleared them and so far, nothing has returned.

so here’s what I think happened: the water in the floor had caused corrosion in one wiring harness. Before I found that, I had removed and checked the CEM. A pin must have gotten bent when I reinstalled it, causing the problem to persist even after I cleaned up the wet harness.

So there you go!