Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information CEM-9F21

Condition




The central electronic module (CEM) receives information about the prevailing light conditions from the twilight sensor. This information is used to determine the light intensity for symbols and the instrument lighting. Two different levels are pre-defined, one for day and one for night. The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers a short-circuit to ground in the twilight sensor circuit.
The diagnostic trouble code (DTC) can be diagnosed at ignition switch position II.

Substitute value
- Light intensity for night is used.

Possible source
- Short-circuit to ground in the signal cable
- The twilight sensor does not operate.

Fault symptom[s]
- The instrument lighting is constantly lit at full strength.