Tech Tip Tuesdays

TechTipTuesdays: Trouble Communicating With BCM or DEM for Volvo Vehicles

VOLVO 2004 XC70

Follow these steps if you are having trouble communicating with your Brake Control Module or Differential Electronic Module.

This test helps diagnose causes for the following symptoms:
– No communication with Brake Control Module
– No communication with Differential Electronic Module (no signal)
– The only fault code in the system is CEM1A64

Disconnect the large connector on the DEM and check to see if communication with the BCM is restored. The DEM will often create network interference, making it impossible to communicate with the BCM until the DEM is removed from the network.


  • Hello
    Im currently having 2 codes. CEM1A64 and BCM0094.
    I tried to disconnect the large connector on the DEM module and im still having the same codes.
    Is this an indicator that it is the BCM module that is the reason for the faults.
    I am also having Anti skid service required message together with a yellow/orange warning sign.

    • same problem and codes here also. Vida can not communicate with the DEM anymore. Just recently opened the DEM module and didn’t find any corrosion or other visual damage. Could it be the wiring harness between the DEM and REM?

      • Hello,
        I’ve forwarded your inquiry to our customer service department. They will be in touch with you shortly via email. Alternatively, you may contact us directly toll-free (US & Canadian customers) 1-888-712-2525 or email
        Thank you,

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