Diagnostic Trouble Code (DTC) Information CEM-1A21

Condition 

Fig 1: Identifying Engine Control Module (ECM)

Courtesy of VOLVO CARS CORPORATION

The central electronic module (CEM) checks the start signal to the engine control module (ECM).

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers a short-circuit to ground in the signal cable for the start signal to the engine control module (ECM).

The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute Value 

• None.

Possible Source 

• Short-circuit to ground in the signal cable.

Fault symptom[s] 

• The engine fails to start
• The starter motor does not turn.