Diagnostic Instructions
| • | 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 the diagnostic category. |
DTC Descriptors
DTC B0248 61: Air Flow Control 3 Circuit Actuator StuckDTC B0268 61: Air Flow Control 7 Circuit Actuator Stuck
DTC B0408 61: Temperature Control 1 Circuit Actuator Stuck
DTC B0413 00: Temperature Control 1 Feedback Circuit
DTC B0418 61: Temperature Control 2 Circuit Actuator Stuck
DTC B0423 00: Temperature Control 2 Feedback Circuit
DTC B0428 61: Temperature Control 3 Circuit Actuator Stuck
DTC B0433 00: Temperature Control 3 Feedback Circuit
DTC B3531 61: Air Flow Control 10 Circuit Actuator Stuck
DTC B3761 00: Air Flow Control 3 Feedback Circuit
DTC B3773 00: Air Flow Control 7 Feedback Circuit
DTC B3782 00: Air Flow Control 10 Feedback Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Recirculation Door Control A | B0268 61 | B0268 61 | -- | -- |
Recirculation Door Control B | B0268 61 | B0268 61 | -- | -- |
Recirculation Door Position Signal | B0268 61 | B3773 00 | B0268 61, B3773 00 | -- |
Recirculation 5-Volt Reference | B0248 61, B0408 61, B0418 61, B0268 61 | B3773 00 | B0268 61, B3773 00 | -- |
Recirculation Low Reference | -- | B0268 61 | -- | -- |
Driver Air Temperature Door Control A | B0408 61 | B0408 61 | -- | -- |
Driver Air Temperature Door Control B | B0408 61 | B0408 61 | -- | -- |
Driver Air Temperature Door Position Signal | B0408 61 | B0413 00 | B0408 61, B0413 00 | -- |
Driver Air Temperature 5-Volt Reference | B0248 61, B0408 61, B0418 61, B0268 61 | B0413 00 | B0408 61, B0413 00 | -- |
Driver Air Temperature Low Reference | -- | B0408 61 | -- | -- |
Passenger Air Temperature Door Control A | B0418 61 | B0418 61 | -- | -- |
Passenger Air Temperature Door Control B | B0418 61 | B0418 61 | -- | -- |
Passenger Air Temperature Door Position Signal | B0418 61 | B0268 61, B0423 00 | B0418 61 | -- |
Passenger Air Temperature 5-Volt Reference | B0248 61, B0408 61, B0418 61, B0268 61 | B0418 61 | B0268 61, B0423 00 | -- |
Passenger Air Temperature Low Reference | -- | B0418 61 | -- | -- |
Mode Door Control A | B0248 61 | B0248 61 | -- | -- |
Mode Door Control B | B0248 61 | B0248 61 | -- | -- |
Mode Door Position Signal | B0248 61 | B0248 61, B3761 00 | B0248 61, B3761 00 | -- |
Mode 5-Volt Reference | B0248 61, B0408 61, B0418 61, B0268 61 | B0248 61 | B0248 61, B3761 00 | -- |
Mode Low Reference | -- | B0248 61 | -- | -- |
Circuit/System Description
The actuators operate using 5 circuits. A 5-volt reference, low reference, signal circuit and two bi-directional 0 or 12 volt control circuits. The HVAC control module supplies a low reference and 5-volt reference to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. As the actuator door changes position the door position signal circuit voltage also changes. The two bi-directional control circuits enable the actuator to operate. Both circuits are set to 0 volts when the HVAC control module detects, from the feedback potentiometer, that the actuator is in the desired position. In order to move the actuator, the HVAC control module switches the appropriate control circuit to 12 volts.
Conditions for Running the DTC
| • | Ignition ON. |
| • | Ignition voltage is between 9-16 volts. |
| • | The HVAC module is ON. |
Conditions for Setting the DTC
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 less than 7 counts or greater than 250 counts.
Action Taken When the DTC Sets
Driver A and driver B circuits are deactivated for the appropriate actuator.
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. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Automatic HVAC Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the appropriate actuator to 100 percent with a scan tool. The scan tool should display between 224 and 230 counts on the mode actuator, all other actuators should display between 199 and 205 counts.
Circuit/System Testing
- Disconnect the harness connector at the appropriate actuator.
- Ignition OFF, test for less than 1 ohm between the low reference circuit terminal 1 and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
- Verify the appropriate scan tool parameter is less than 4 counts.
- Install a 3A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 1. Verify the appropriate scan tool parameter is greater than 250 counts.
- Ignition ON, after 30 seconds verify that a test lamp illuminates between control circuit A terminal 5 and B+.
- Ignition OFF, verify that the test lamp does not illuminate between control circuit A terminal 5 and B+.
- Ignition ON, after 30 seconds verify that a test lamp illuminates between control circuit B terminal 4 and B+.
- Ignition OFF, verify that the test lamp does not illuminate between control circuit B terminal 4 and B+.
- If all circuits test normal, test or replace the actuator.
| ⇒ | If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If greater than the specified range, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal replace the HVAC control module. |
| ⇒ | If the test lamp illuminate, test the control circuit for a short to ground. If circuit tests normal replace the HVAC control module. |
| ⇒ | If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal replace the HVAC control module. |
| ⇒ | If the test lamp illuminate, test the control circuit for a short to ground. If circuit tests normal replace the HVAC control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for HVAC control module replacement, setup, and programming |
