2004 XC70 Instrument Cluster Issues

[BlackBart]

I got a response back from Xemodex this morning. I felt good about getting this working, but now I have more doubts. I'll quote it:


"You're describing a lot of things that wouldn't be caused by a DIM. A DIM from this year wouldn't cause issues with other modules. They only bring themselves down. It's also not possible for a DIM to cause issues with idling (which for clarification was listed on your fault symptoms report, so it's not new since the DIM repair).

"A very likely culprit for this issue is the Central Electronic Module (CEM). Very common issue in 2004, and would cause issues like you're describing as it disrupts the entire low-speed network, and eventually causes issues with the high-speed network when it gets bad enough.

"Before doing anything with the CEM though, I would strongly recommend getting the vehicle to a Volvo specialist for diagnosis. At the very least, getting a full code readout may help narrow things down.

"I looked briefly for Volvo specialists in your area, but didn't see any names I recognize. Finding a shop that uses Volvo compatible scan tools like VIDA or AutoLogic will be key.

"Let me know how it goes, or if you have any questions."

[BlackBart]

Wow.... I'm hoping I didn't do all that solder repair and shipping DIM's and buying a replacement and it wasn't actually the DIM...

viewtopic.php?p=606660&hilit=CEM#p606660

EDIT> Although, my dash clock was wonky from the day we got this car, so there was something going on there with the DIM.

[firstv70volvo]

Well I'm getting an unexpected electronics lesson with this, generally above my pay grade!

Is the LSM right there behind the switch itself? It was the connection to the CEM, or the module that was the problem?

(See next post with response from Xemodex)..........

Yes, the LSM is a small circuit board behind the switch itself. In my car it was the LSM circuit board that was the problem, a bad solder joint, in your car it was the CEM and what appears to have been a power delivery problem to the CEM itself.


Here's the LSM circuit board and my notes/labeling after working on the board.

volvo light switch module circuit board top side view with labeling.jpg (250.77 KiB) Viewed 493 times

[BlackBart]

Wow.
I just looked up this diagnostics chart -

https://xemodex.com/us/dim-cem-low-spee ... flowchart/

[firstv70volvo]

I got a response back from Xemodex this morning. I felt good about getting this working, but now I have more doubts. I'll quote it:


"You're describing a lot of things that wouldn't be caused by a DIM. A DIM from this year wouldn't cause issues with other modules. They only bring themselves down. It's also not possible for a DIM to cause issues with idling (which for clarification was listed on your fault symptoms report, so it's not new since the DIM repair).

"A very likely culprit for this issue is the Central Electronic Module (CEM). Very common issue in 2004, and would cause issues like you're describing as it disrupts the entire low-speed network, and eventually causes issues with the high-speed network when it gets bad enough.

"Before doing anything with the CEM though, I would strongly recommend getting the vehicle to a Volvo specialist for diagnosis. At the very least, getting a full code readout may help narrow things down.

"I looked briefly for Volvo specialists in your area, but didn't see any names I recognize. Finding a shop that uses Volvo compatible scan tools like VIDA or AutoLogic will be key.

"Let me know how it goes, or if you have any questions."

The problems you were having was related to the CEM and after you pulled, checked and reinstalled the fuses everything started working again so it was very likely one of three different power sources to the CEM were missing or low voltage and very likely a poor contact with one of the fuse contacts. I don't think the problem is with the CEM itself based on what you did and when it started working again. Did you have anything like this happen in the past? From your original post your DIM was having some issues but I don't know what other problems you may had previously and if any seem related to the CEM.
How's the car doing now, any new problems?

[BlackBart]

No, the instrument panel issues all happened suddenly while my wife was driving. She couldn't see any gauge info and the turn signals wouldn't work. She very cautiously brought it home. We didn't drive it after that, then I pulled the DIM and tried to repair.

The wildly speeding clock on the cluster was always there. It would randomly stop and we could see the temp gauge, which is a nice thing to have. I always assumed it was a mechanical switch problem on the tiny dial / stick.

[firstv70volvo]

No, the instrument panel issues all happened suddenly while my wife was driving. She couldn't see any gauge info and the turn signals wouldn't work. She very cautiously brought it home. We didn't drive it after that, then I pulled the DIM and tried to repair.

The wildly speeding clock on the cluster was always there. It would randomly stop and we could see the temp gauge, which is a nice thing to have. I always assumed it was a mechanical switch problem on the tiny dial / stick.

Okay, so this does look more like CEM related problem, in addition to the gauges going out and the turn signals not working, were there any more of the same problems as you mentioned after the DIM replacement such as no auto lock, windows, sunroof etc?

[BlackBart]

Nope, everything is working well.

[firstv70volvo]

Nope, everything is working well.

Good deal, you got your DIM repaired and you found and repaired the other problem too.

[BlackBart]

I hope. Now I'm reading all these CEM failure posts, and hearing that 2004 has this problem. I thought I bought a reliable Volvo, not an old Jaguar with random electrical problems....

I asked my Xemodex man more detail on the CEM issue. He says the CEM overheats over time, which first causes issues with the low speed network, and as time goes by it starts to affect the high speed network.

I don't know where the low-speed and high-speed occur / exist in this system.

I asked if it's a time and hours problem, or a hot climate problem. He said both - over time the CEM overheats, causing a tiny amount of damage on the board. It becomes more prominent when it's hot, but the damage is already done.