Diagnostic trouble code (DTC) information CEM-1A42

Condition 

Fig 1: Identifying Central Electronic Module (CEM)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) has an internal clock which starts when the control module is powered for the first time in the factory. The time is kept from the time the internal timer circuit started.

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers that the real time clock is giving an incorrect value.

The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on and when the test is run at least once a minute.

Substitute Value 

• None.

Possible Source 

• Internal fault in the central electronic module (CEM).

Fault symptom[s] 

• The parking heater does not operate.
• The clock in the information module is not working