Diagnostic trouble code (DTC) information CEM-1A64

Condition 

Fig 1: Identifying Active On Demand Coupling Control Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers that communication with the differential electronic module (DEM) is not operating.

The diagnostic trouble code (DTC) can be diagnosed when the ignition has been on for more than 10 seconds.

Substitute Value 

• None.

Possible Source 

• No power supply to the differential electronic module (DEM)
• Open-circuit in the ground lead for the differential electronic module (DEM)
• Contact resistance in the terminals
• Open-circuit in the wiring for the CAN high speed network to the differential electronic module (DEM)
• The differential electronic module (DEM) is not intended for this vehicle, for example a used control module with different software/hardware.

HINT: If several diagnostic trouble codes (DTCs) are stored in the central electronic module (CEM) for communication faults with other control modules in the high speed network, this indicates a common fault in the Control area network, see the wiring diagram. 

Fault symptom[s] 

• Four wheel drive is not functioning.
• Message in the display
• General warning lamp lit