Diagnostic Trouble Code (DTC) Information ECM-A20B

Condition 

The central electronic module (CEM) transmits a timer signal to the control modules in the car via the controller area network (CAN). This signal informs how many seconds have passed since the engine was last switched off. The signal is used for example by the engine control module (ECM) when restarting a warm engine. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers that the timer signal transmitted by the central electronic module (CEM) is incorrect.

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

Substitute Value 

A calculated timer signal is used by the engine control module (ECM).

Possible Source 

• Fault trace the central electronic module (CEM)
• Open-circuit or short-circuit in CAN wiring between the engine control module (ECM) and the central electronic module (CEM)
• Damaged central electronic module (CEM).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.