Diagnostic trouble code (DTC) information CEM-5F46

Condition 

Fig 1: Identifying Glow Plug

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 a short-circuit to ground in the power supply from the combustion preheater module (CPM) to the glow plug or that there is no power at all.

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

Substitute Value 

• None.

Possible Source 

• Damaged glow plug.
• Contact resistance in the control module connectors
• Contact resistance in the glow plug connection.
• Short-circuit to ground in the signal cable
• Short-circuit to supply voltage in the signal cable
• Open-circuit in the signal cable

Fault symptom[s] 

• Poor heating in the passenger compartment.