Cabin Heater Control Circuit Open (Active)

Test 1:

Test 2 - 4:

Test 5 - 6:

Test 7 - 8:

SYMPTOM
CABIN HEATER CONTROL CIRCUIT OPEN (ACTIVE)

WHEN MONITORED
When the DCHA system is off

SET CONDITION
The DCHA Low Side Driver inside the FCM expects to see a system voltage of 13.8 volts through the DCHA relay coil when the DCHA system is off. This DTC will set if the FCM sees a voltage below 3.5 volts on the Cabin Heater Assist Control circuit during this time.

POSSIBLE CAUSES
- No response from cabin heater module
- Cabin heater assist control circuit open to IPM
- IPM, open circuit
- FCM, open circuit
- FCM fault
- Cabin heater assist control circuit shorted to the ground circuit
- Cabin heater assist control circuit shorted to ground
- Cabin heater assist control circuit open
- DCHA control unit fault