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 Radio/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 (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Automatic HVAC Description and Operation (Description and Operation)
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 (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition ON, press and release the POWER switch. Verify the scan tool Front HVAC System Status parameter changes between Off and On.
• If not the specified value, replace the A20 Radio/HVAC Controls.
2. 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 A20 Radio/HVAC Controls.
3. 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 A20 Radio/HVAC Controls.
4. Press and release the automatic recirculation switch. Verify the scan tool Air Quality Sensor Switch parameter changes between On and Off.
• If not the specified value, replace the A20 Radio/HVAC Controls.
5. Verify the M46 Air Recirculation Door Motor can be put into all positions.
• If the M46 Air Recirculation Door Motor cannot be put into all positions, replace the M46 Air Recirculation Door Motor and verify the M46 Air Recirculation Door Motor can be put into all positions.
6. 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 (Verification Tests) after completing the diagnostic procedure.
* Inside Air Valve Actuator Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup and programming