B0424

DTC B0130, B0414, or B0424

Circuit Description

The HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC system. Each actuator consists of an electric motor and a potentiometer. The potentiometer inside the door actuator allows the module to monitor the current position of the actuator drive shaft. The module supplies a 5-volt source voltage to the potentiometer on the 5-volt reference circuit. The module supplies ground to the potentiometer through the low reference circuit. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage on the door position signal circuit changes.

* Air flow position feedback circuit refers to the mode actuator.
* Temperature control 1 feedback circuit refers to the driver air temperature actuator.
* Temperature control 2 feedback circuit refers to the passenger air temperature actuator.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

* DTC B0130 Air Flow Position Command Circuit Range
* DTC B0414 Temperature Control 1 Feedback Circuit
* DTC B0424 Temperature Control 2 Feedback Circuit

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

The HVAC control module detects the door position signal circuit is less than 7 counts or greater than 250 counts for 1 minute.

Action Taken When the DTC Sets

The HVAC control module uses only the minimum and maximum door positions.

Conditions for Clearing the DTC

* The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 50 fault-free ignition cycles.
* The DTC can be cleared with a scan tool.

Test Description

Step 1 - Step 9:

Step 10 - Step 17:

The number below refers to the step number on the diagnostic table.
4. This step verifies that the HVAC control module is able to command the appropriate HVAC actuator.