CCM-0020

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.

Condition
- 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.

Condition
- Poor air quality in the passenger compartment.