Damper Motor Module (DMM) Change

[rjtire555]

Hi all,

I have an associated post which described the symptoms which culminated in this issue which is now very specific so I've created a dedicated post - hope this is okay.

I'm particularly keen to solicit feedback from anyone who has changed one of the temperature DMMs in their car successfully.

Long story short - passenger side temp was stuck on hot and heated seats were dead. Assumed LIN related so tried changing heated seat controller and AQS without resolving the issue. Under suggestion from SwissXC90, I tested with VIDA and observed CCM-0070 and CCM-0071. Failed DMM for the passenger temp.

Bought a new DMM from local Volvo dealer for €185. Fitted it successfully (I think). However, a CCM calibration still fails reporting a permanent fail for the DMM.

I've tried running the "Identification of damper motors, status" routine but this can run for over 30 minutes without completing. However, when I run it, I can see that it does exercise the motor which I've replaced, which in turn moves the damper.

So, given the diagnostic routine can move the damper, I assume the hardware is correct. The passenger side temp is now cold (better for summer at least) and the heated seats are back functional but the car still reports that the DMM is a permanent fault and the dashboard controls don't move the motor.

Please, please, please - if anyone has any experience of this, can you let me know?!

I've contacted my local Volvo dealer who looked at the car before Christmas when the heating system wasn't working correctly (without success) and their only suggestion was to book in for an hour of labour + VAT at a pretty eye watering rate. Given my experience with them, I think it'd be money down the drain....

Cheers,
Joe

[rjtire555]

It's starting to look like a trip to Volvo is my only answer here unless some damper motor module mogul is hiding out there!

[rjtire555]

Hi all.

Closure on my issue has been attained finally.

The issue manifested in my XC90 as the passenger side temperature DMM not adjusting the damper in response to the temperature being changed. I replaced the DMM to no effect.

After changing the DMM, when I would run the LIN identification routine, it would sit in a running state without indicating that something was wrong. This routine should complete in about 2 minutes. Ergo - if it doesn't complete in 2 minutes, there's still something wrong with your system.

After a lot of head scratching, I noticed that the air recirculation damper mechanism seemed to be wedged by a loose control module for the aftermarket front parking sensors originally fitted by the supplying garage. After this was removed, the LIN identification routine completed successfully.

Advice for people with CCM issues: There are many posts on here and other forums suggesting fixes. The interconnected nature of the modules, via LIN, seems to inhibit functions anywhere in the network if something is awry. In many cases, the fix is an AQS. In some cases, it is a faulty heated seat controller or DMM. In my case, it was a mechanism being jammed. So, before you do replace anything, expose all of your CCM LIN components and ensure that the mechanical systems can act as intended.

I'm preparing to put my dash back together.

Thanks to cheshired5 for all the help in getting software up and running and any posters who've guided this debug along the way.

[cheshired5]

Logical and calm persistence always wins out.
Well done on the fix and helpful description.