B0238 - HVAC Systems - Automatic

Schematic:

CIRCUIT DESCRIPTION
The mode door actuator is an electronic stepper motor without a feedback circuit. It responds to voltage inputs from the heater and A/C control with precalibrated non-adjustable position settings. The heater and A/C control adjusts the mode door actuator position to direct airflow from the outlets selected by the vehicle occupants.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is turned ON.
^ DTC B1327 must not be current.

CONDITIONS FOR SETTING THE DTC
The mode actuator motor control circuit is shorted to ground or shorted to B+ for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
Control of the mode door position will be disabled.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the heater and A/C control no longer detects a failure.
^ The history DTC will clear after 50 fault free ignition cycles
^ The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-9:

The numbers below refer to the step numbers on the diagnostic table.
2. The mode door actuator can be driven to one of two positions using the Defrost and A/C command keys on the scan tool. The scan tool displays module output as a percentage of maximum control voltage. It does not indicate true actuator or door position.
3. This step verifies that the actuator is receiving the control voltage.