Volvo XC90 – CCM Reset to remedy HVAC blend door noise

 

May 4th, 2016

Every now and then, I noticed a hooting owl coming from the dashboard. Not too intrusive a sound, but then again when it came to this noise I still conjured up the Tears for Fears lyrics “these are the things I can do without”.

I eventually took a video and uploaded it. I ran it past some folks on the SwedeSpeed forum for confirmation. I had assumed it was one of the doors that redirected the airflow in the HVAC system, or perhaps a bad bearing in the blower motor, but given the paucity of other symptoms I was coming up dry otherwise. A number of posts/threads in the forum suggested replacement of the blend door motors, which is rather labor-intensive. Others suggested resetting the CCM (Climate Control Module), which is performed with VIDA and a DiCE unit. Since a reset takes first precedence over an RMA, the next steps were logical.

Once the DiCE unit is connected to VIDA, test the communication using the “vehicle profile” tab. Select the DiCE unit from the drop-down menu. If the communication test is unsuccessful, check the LEDs on your DiCE to ensure a logical connection has been established. Check your USB drivers and whether the DiCE unit is detected. If you are using a Windows 7 virtual machine, ensure that the physical USB interface has been assigned to the virtual machine instance you are utilizing. In a virtualbox setup this requires clicking the USB icon on the right side of the taskbar and clicking on the DiCE unit.

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An interesting note is that “working sound from the damper motors may exist”. I presume this means the initial startup sounds, but probably not the constant hooting owl (others described it as dogs barking in the distance).

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The engine should not be running; if it is, the DiCE unit will become logically disconnected when the calibration is started. Turn it to ignition position II as described in the “Calibrating the CCM” fault trace guide. Click on the VCT2000 symbol to begin the test. The blend doors in the dashboard will all actuate. Wait a minute or so after the test has been completed before turning the ignition off.

 

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If the Climate Control Module (CCM) reset has been completed successfully, you will be presented with the message below. If a CCM reset does not remedy the noise, I would suggest performing the procedure one more time in the event that a blend door was physically stuck. If the noise persists after multiple CCM resets I would suggest re-evaluating the source of the noise by testing various HVAC settings to ensure it is a blend door (fan off/on/low/high, recirc, AC compressor on/off, upper/mid/lower vents open and shut, etc). After that I would suggest assessment by a qualified service facility for possible hardware replacement.

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