Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information CEM-B1D1A12

Condition
The Central electronic module (CEM) supplies voltage to the roof lighting. The power supply is a PWM signal (Pulse Width Modulated).
The diagnostic trouble code (DTC) is stored if the control module detects that:
- Signal too high from the output.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Control module supplied with power.
- Activated interior lighting.

Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.

Substitute value
- The function switches off permanently after 100 operating cycles where the fault was detected. Erasing diagnostic trouble codes (DTCs) resets the result.

Possible source
- The cable for voltage feed is short-circuited to voltage.

Fault symptom[s]
- Interior light does not work
- Interior light does not extinguish when engine is running