Diagnostic Trouble Code (DTC) Information CEM-8C20

Condition 

Fig 1: Identifying Tail Lamps

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) powers the rear fog lamp directly via an output. The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers that the power consumption for the output is too low.

The diagnostic trouble code (DTC) can be diagnosed at key positions I and II.

Substitute Value 

• None.

Possible Source 

• Short-circuit to battery voltage in the signal cable to the rear fog lamp
• Open-circuit in the signal cable to the rear fog lamp
• One or more lamps are defective or missing.

Fault symptom[s] 

• The rear fog lamp does not work
• The rear fog lamp is constantly lit.