HVACAir Recirculation Malfunction
Air Recirculation Malfunction
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
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Stepper Motors 12V Reference
|
B023A 02, B0223 06, B022A 06, B0233 06, B0408 06, B0418 06
|
B0223 06, B022A 06, B0233 06, B0408 06, B0418 06
|
-
|
-
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Air Recirculation Actuator Control 1
|
B0223 06
|
B0223 06
|
B0223 01
|
1
|
Air Recirculation Actuator Control 2
|
B0223 06
|
B0223 06
|
B0223 01
|
1
|
Air Recirculation Actuator Control 3
|
B0223 06
|
B0223 06
|
B0223 01
|
1
|
Air 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 air recirculation flap can be set
with the recirculation switch at the HVAC controls. 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 air recirculation flap. In the
recirculation mode the air inlet flap closes and the air
recirculation flap opens in order to circulate the air within the
vehicle. In fresh air mode the air inlet flap opens and the air
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 air recirculation flap and fresh air flap into the
selected position.
Diagnostic Aids
Check the following mechanical fault sources:
| • |
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
Scan Tool Reference
Control Module References for scan tool information
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 air
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
| |
3.1 |
Ignition OFF, replace the M46
Air Recirculation Door Actuator, ignition ON. |
| |
3.2 |
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
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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12 Heating & A/C
