Air Temperature Malfunction
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Stepper Motors 12V Reference
|
B023A 02, B0223 06, B0233 06, B0418 06
|
B0223 06, B0233 06, B0418 06
|
-
|
-
|
Air Temperature Actuator Control 1
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator Control 2
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator Control 3
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator Control 4
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
1. Air Temperature Malfunction
|
|
| |
Circuit/System Description
With the temperature switch at the HVAC control, the desired air
temperature flap position can be put in. 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 temperature flap into the calculated
position, in order to reach the selected temperature.
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
Manual HVAC Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Measure actual evaporator
temperature using a thermometer. Compare this value to the scan
tool A/C Evaporator Temperature Sensor parameter. The measured
temperature should be within 5°C (9°F) difference of
parameter value. |
⇒ If not within the
specified range
Refer to
DTC B3933 . ⇓
If within the specified range
| 2. |
Engine is running, activate
and deactivate the A/C switch. Verify the A/C compressor can be
activated and deactivated. |
⇒ If the A/C
compressor cannot be activated or deactivated
Refer to
Air Conditioning Compressor Malfunction .
⇓ If the A/C
compressor can be activated or deactivated
| 3. |
Verify the engine reaches its
operating temperature. |
Circuit/System Testing
| 1. |
Ignition ON, turn the
temperature knob in all positions. Verify the scan tool Left
Temperature Knob Position parameter. The reading should correspond
to the selected temperature. |
⇒ If not the
specified value
Replace the A26 HVAC Controls.
⇓ If the specified
value
| 2. |
Replace the M6 Air Temperature
Door Actuator and verify the M6 Air Temperature Door Actuator can
be put into all positions. |
⇒ If the M6 Air
Temperature Door Actuator cannot be put into all
positions
Replace the K33 HVAC Control Module.
⇓ If the M6 Air
Temperature Door Actuator can be put into all
positions
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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