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 each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Stepper Motors 12 V Reference | B023A 02, B0223 06, B022A 06, B0233 06, B0408 06, B0418 06 | B0223 06, B022A 06, B0233 06, B0408 06, B0418 06 | -- | -- |
Recirculation Actuator Control 1 | B0223 06 | B0223 06 | B0223 01 | 1 |
Recirculation Actuator Control 2 | B0223 06 | B0223 06 | B0223 01 | 1 |
Recirculation Actuator Control 3 | B0223 06 | B0223 06 | B0223 01 | 1 |
Recirculation Actuator Control 4 | B0223 06 | B0223 06 | B0223 01 | 1 |
Air Inlet Actuator Control 1 | B022A 06 | B022A 06 | B022A 01 | 1 |
Air Inlet Actuator Control 2 | B022A 06 | B022A 06 | B022A 01 | 1 |
Air Inlet Actuator Control 2 | B022A 06 | B022A 06 | B022A 01 | 1 |
Air Inlet Actuator Control 2 | B022A 06 | B022A 06 | B022A 01 | 1 |
1. Air Recirculation Malfunction | ||||
Circuit/System Description
The desired position of the recirculation flap can be set with the recirculation switch at the HVAC control. The selected value is sent to the HVAC control module via the LIN-Bus. Two stepper motors are used for the recirculation and fresh air control. The first stepper motor moves the air inlet flap, the second stepper motor moves the recirculation flap. In the recirculation mode the air inlet flap closes and the recirculation flap opens in order to circulate the air within the vehicle. In fresh air mode the air inlet flap opens and the recirculation flap is closed again in order to route outside air into the vehicle. The HVAC control module supplies a 12 V reference voltage to both stepper motors and energizes the appropriate 4 stepper motor coils with a pulsed ground signal. The stepper motor puts the recirculation flap and fresh air flap into the selected position.
Diagnostic Aids
Check the following mechanical fault sources:
| • | Air distribution box |
| • | Air distribution hoses / air distribution ducts |
Reference Information
Schematic Reference
LINK 49327
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 Testing
- Ignition ON, press and release the defrost switch. Verify the scan tool Enhanced Defrost Switch parameter changes between Active and Inactive.
- Ignition ON, press and release the recirculation switch. Verify the scan tool Air Recirculation Mode Switch parameter changes between Active and Inactive.
- Verify the M46 Recirculation Actuator can be put into all positions.
- If all circuits test normal, replace the M4 Air Inlet Actuator and verify the M4 Air Inlet Actuator can be put into all positions. If the M4 Air Inlet Actuator cannot be put into all positions, replace the K33 HVAC Control Module.
| ⇒ | If not the specified value, replace the A26 HVAC Control. |
| ⇒ | If not the specified value, replace the A26 HVAC Control. |
| ⇒ | If the M46 Recirculation Actuator cannot be put into all positions, replace the M46 Recirculation Actuator and verify the M46 Recirculation Actuator can be put into all positions. If the M46 Recirculation Actuator cannot be put into all positions, replace the K33 HVAC Control Module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | LINK 63253 |
| • | Control Module References for HVAC control module replacement, setup, and programming |
