Diagnostic trouble code (DTC) information CEM-5F4C

Condition 

Fig 1: Identifying Additional Heater And Parking Heater

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (HEM) checks the communication with the combustion preheater module (CPM).

The diagnostic trouble code (DTC) is stored if the central electronic module (HEM) registers that the power supply to the combustion preheater module (CPM) is below 10.5 V.

The diagnostic trouble code (DTC) can be diagnosed when the heater is activated.

Substitute Value 

• None.

Possible Source 

• Poor battery
• Contact resistance in the control module terminals
• Damaged generator (GEN).

Fault symptom[s] 

• Poor heating in the passenger compartment.