• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Recirculate Position Command Circuit A | B0223 04, 06 | B0223 04, 06 | B0223 05, 06 | B0223 61 |
Recirculate Position Command Circuit B | B0223 04, 06 | B0223 04, 06 | B0223 05, 06 | B0223 61 |
Mode Door Control Circuit A | B0233 04, 06 | B0233 04, 06 | B0233 05, 06 | B0233 61 |
Mode Door Control Circuit B | B0233 04, 06 | B0233 04, 06 | B0233 05, 06 | B0233 61 |
Driver Air Temperature Door Control A Circuit | B0408 04, 06 | B0408 04, 06 | B0408 05, 06 | B0408 61 |
Driver Air Temperature Door Control B Circuit | B0408 04, 06 | B0408 04, 06 | B0408 05, 06 | B0408 61 |
Passenger Air Temperature Door Control A Circuit | B0418 04, 06 | B0418 04, 06 | B0418 05, 06 | B0418 61 |
Passenger Air Temperature Door Control B Circuit | B0418 04, 06 | B0418 04, 06 | B0418 05, 06 | B0418 61 |
The actuator is an electronic stepper motor. The HVAC control module supplies power and ground to the actuator. The HVAC control module controls the direction of the actuator by changing the polarity of the control circuits. When the actuator reaches its desired position, both circuits are fixed to the same value 0 volts. The HVAC control module determines the door position by counting pulses, voltage fluctuations, caused by the brush to commutator action generated during normal motor operation. The HVAC control module monitors a voltage drop across an internal resistance to detect the pulses. The HVAC control module converts the pulses to counts with a range of 0-255 counts.
• | The ignition is ON. |
• | Ignition voltage is between 9-16 volts. |
• | The HVAC module is ON. |
The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is shorted to ground shorted to voltage or open.
Driver A and driver B circuits are deactivated for the appropriate actuator.
• | 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. |
Control Module References for scan tool information
⇒ | If the test lamp is always OFF, test the appropriate control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
⇒ | If the test lamp continuously illuminates, test the appropriate control circuit for a short to B+. If the circuit tests normal, replace the HVAC control module. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for HVAC control module setup, replacement, and programming |