Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition




Diagnostic trouble code (DTC) CCM-0020 is stored if the control module registers that the signal from the air quality sensor has a pulse length which is less than 3% of the period.
The diagnostic trouble code (DTC) CCM-0020 can only be diagnosed for electronic climate control modules (CCM) (ECC versions) with air quality sensors.

Substitute value
- The control module does not permit the recirculation shutter to close in the air quality sensor mode while the fault persists
- No air quality sensor function.

Possible source
- Short-circuit to ground in the signal cable between the control module and the air quality sensor.

Fault symptom[s]
- Poor air quality in the passenger compartment.