Checking components

The diagnostic trouble code (DTC) indicates that the communication between the additional heater module and the central electronic module (CEM) is interrupted. This may be due to a fault in the cable between the control modules or a defective communication device in one or both of the control modules.

Check the cable between central electronic module (CEM) connector terminal #18A and additional heater terminal #6. Check for an open-circuit. Check for a short-circuit to ground.

Other information: 

• See Checking wiring and terminals .

Fig 1: Identifying Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Ohm Meter

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: Control Module Terminals (1 Of 2)

Courtesy of VOLVO CARS OF NORTH AMERICA.

Was a fault detected? 

• YES 

  Refer to Verification 

• NO 

  Refer to Replacing the additional heater module