For 1990-2009 cars

## Air Recirculation Malfunction C68

### 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, B0233 06, B0408 06 | B0223 06, B0233 06, B0408 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
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. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor moves the recirculation 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

HVAC Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Automatic HVAC Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Ignition ON, press and release the defrost switch. Verify the scan tool Enhanced Defrost Switch parameter changes between Active and Inactive.

⇒ | If not the specified value, replace the A26 HVAC Control.

2. Ignition ON, press and release the recirculation switch. Verify the scan tool Air Recirculation Mode Switch parameter changes between Active and Inactive.

⇒ | If not the specified value, replace the A26 HVAC Control.

3. If all circuits test normal, replace the M46 Recirculation Actuator and verify the M46 Recirculation Actuator can be activated and deactivated. If the M46 Recirculation Actuator cannot be activated or deactivated, replace the K33 HVAC Control Module.

### Repair Instructions

Perform the Diagnostic Repair Verification

• | Recirculation Actuator Replacement

• | Heater and Air Conditioning Control Replacement

• | Control Module References

## Air Recirculation Malfunction CJ2

### 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

HVAC Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Automatic HVAC Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Ignition ON, press and release the defrost switch. Verify the scan tool Enhanced Defrost Switch parameter changes between Active and Inactive.

⇒ | If not the specified value, replace the A26 HVAC Control.

2. Ignition ON, press and release the recirculation switch. Verify the scan tool Air Recirculation Mode Switch parameter changes between Active and Inactive.

⇒ | If not the specified value, replace the A26 HVAC Control.

3. Verify the M46 Recirculation Actuator can be put into all positions.

⇒ | 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.

4. 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.

### Repair Instructions

Perform the Diagnostic Repair Verification

• | Recirculation Actuator Replacement

• | Air Inlet Valve Actuator Replacement

• | Heater and Air Conditioning Control Replacement

• | Control Module References