Air Recirculation Malfunction
Air Recirculation Malfunction
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 control. The selected value is passed 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 puts 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 (HVAC - Manual)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Manual HVAC Description and Operation (HVAC - Manual)
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, activate and deactivate 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. Activate and deactivate 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.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Heater and Air Conditioning Control Replacement (HVAC - Automatic)
* Air Inlet Valve Actuator Replacement (Air Inlet Valve Actuator Replacement)
* Control Module References (Programming and Relearning)