Air Recirculation Malfunction (CJ2)
Air Recirculation Malfunction (CJ2)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The desired position of the recirculation flap can be set with the recirculation switch at the HVAC controls. The selected value is sent to the HVAC control module via 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 HVAC - Automatic
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
Automatic HVAC Description and Operation HVAC - Automatic
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References 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 the parameter does not change
Replace the A26 HVAC Controls.
• If the parameter changes
2. Press and release the recirculation switch. Verify the scan tool Air Recirculation Mode Switch parameter changes between Active and Inactive.
• If the parameter does not change
Replace the A26 HVAC Controls.
• If the parameter changes
3. Verify the M46 Air Recirculation Door Actuator can be put into all positions.
• If the M46 Air Recirculation Door Actuator cannot be put into all positions
1. Ignition OFF, replace the M46 Air Recirculation Door Actuator, ignition ON.
2. Verify the M46 Air Recirculation Door Actuator can be put into all positions.
• If the M46 Air Recirculation Door Actuator cannot be put into all positions, replace the K33 HVAC Control Module.
• If the M46 Air Recirculation Door Actuator can be put into all positions, all OK.
• If the M46 Air Recirculation Door Actuator can be put into all positions
4. Replace the M4 Air Inlet Door Actuator and verify the M4 Air Inlet Door Actuator can be put into all positions.
• If the M4 Air Inlet Door Actuator cannot be put into all positions
Replace the K33 HVAC Control Module.
• If the M4 Air Inlet Door Actuator can be put into all positions
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Air Inlet Valve Actuator Replacement Air Inlet Valve Actuator Replacement
* Heater and Air Conditioning Control Replacement Heater and Air Conditioning Control Replacement
* Control Module References Control Module References for HVAC control module replacement, programming and setup