Diagnostic trouble code (DTC) information
Condition
Diagnostic trouble code (DTC) CCM-0021 is stored if the control module registers that the signal from the air quality sensor has a pulse length which is between 48% and 50% of the period.
The diagnostic trouble code (DTC) CCM-0021 can only be diagnosed for electronic climate control modules (CCM) (ECC version) 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
- Internal fault in the circuit for the air quality sensor function.
Fault symptom[s]
- Poor air quality in the passenger compartment.