Diagnostic trouble code (DTC) informationCEM-1A67

Condition

Fig 1: Identifying Headlight Control Module (HCM)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The diagnostic trouble code (DTC) is generated if the central electronic module (CEM) registers that communication with the headlight control module (HCM) is not operating.

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

NOTE:

If CEM-1A6X diagnostic trouble codes (DTCs) are stored, the central electronic module (CEM) must not be replaced as the diagnostic trouble code (DTC) indicates a communication fault in the Control area network

Substitute Value

None.

Possible Source

Voltage feed to Headlight Control Module (HCM) missing.
Open circuit on ground cable to Headlight Control Module (HCM)
Contact resistance in the terminals
Open circuit on CAN cables to headlight control module (HCM).
Headlight Control Module (HCM) not intended for this car, e. g., used control module with other hardware/software.

HINT: If several diagnostic trouble codes for communication errors with other control modules in the high-speed network are stored in the Central electronic module (CEM), this indicates some common problem in the CAN-network (see wiring diagram).

Fault symptom[s]

Active Bi-Xenon light; No Functionality