Diagnostic trouble code (DTC) information CEM-8A21

Condition 

Fig 1: Identifying Central Electronic Module (CEM)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) powers the right-hand low beam 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 high.

The diagnostic trouble code (DTC) can be diagnosed when the ignition has been on for more than 40 seconds.

Substitute Value 

• If the fault has been detected in 200 ignition cycles, the output is closed permanently until the diagnostic trouble code is erased.

Possible Source 

• Short-circuit to ground in the low beam signal cable.

Fault symptom[s] 

• Low beam does not work.