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, B022A 06, B0233 06, B0408 06, B0418 06
|
B0223 06, B022A 06, B0233 06, B0408 06, B0418 06
|
-
|
-
|
Air Temperature Actuator - Left Control 1
|
B0408 06
|
B0408 06
|
B0408 01
|
1
|
Air Temperature Actuator - Left Control 2
|
B0408 06
|
B0408 06
|
B0408 01
|
1
|
Air Temperature Actuator - Left Control 3
|
B0408 06
|
B0408 06
|
B0408 01
|
1
|
Air Temperature Actuator - Left Control 4
|
B0408 06
|
B0408 06
|
B0408 01
|
1
|
Air Temperature Actuator - Right Control 1
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator - Right Control 2
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator - Right Control 3
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
Air Temperature Actuator - Right Control 4
|
B0418 06
|
B0418 06
|
B0418 01
|
1
|
1. Air Temperature Malfunction
|
|
| |
Circuit/System Description
With the temperature switches at the HVAC controls, the wished
air temperature flap position can be put in. The selected values
are sent to the HVAC control module via LIN-Bus. The HVAC control
module supplies a 12 V reference voltage to the stepper motors and
energizes the 4 stepper motor coils with a pulsed ground signal.
The stepper motors put the mixed air flaps 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
Automatic HVAC Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Ignition ON, measure actual
inside air temperature using a thermometer. Compare this value to
the scan tool Passenger Compartment Air Temperature parameter. The
measured temperature should be within 5°C (9°F) difference
of parameter value. |
⇒ If not within the
specified range
Refer to
DTC B0163, B0183, or B1405 .
⇓ If within the
specified range
| 2. |
Measure actual temperature
using a thermometer at each of the duct temperature sensors.
Compare this value to the appropriate scan tool Duct Actual
parameter. The measured temperature should be within 5°C
(9°F) difference of appropriate Duct Actual parameter
value. |
⇒ If not within the
specified range
Refer to
DTC B0173, B0178, B0509, B0514 or B3933 .
⇓ If within the
specified range
| 3. |
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 B0173, B0178, B0509, B0514 or B3933 .
⇓ If within the
specified range
| 4. |
Observe the scan tool Sunload
parameter. The reading should be between 50-1 150 W/m² and
change with sunlight intensity. |
⇒ If not within the
specified range or not change
Refer to
DTC B0163, B0183, or B1405 .
⇓ If the value
changes within the specified range
| 5. |
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
| 6. |
Verify the engine reaches its
operating temperature. |
Circuit/System Testing
| 1. |
Ignition ON, turn the left
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. |
Turn the right temperature
knob in all positions. Verify the scan tool Right 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
| 3. |
Verify the M6L Air Temperature
Door Actuator - Left can be put into all positions. |
⇒ If the M6L Air
Temperature Door Actuator - Left cannot be put into all
positions
| |
3.1 |
Ignition OFF, replace the M6L
Air Temperature Door Actuator - Left, ignition ON. |
| |
3.2 |
Verify the M6L Air Temperature
Door Actuator - Left can be put into all positions. |
| ⇒ |
If the M6L Air Temperature Door Actuator - Left cannot be put
into all positions, replace the K33 HVAC Control Module. |
| ⇒ |
If the M6L Air Temperature Door Actuator - Left can be put into
all positions, all OK. |
⇓ If the M6L Air
Temperature Door Actuator - Left can be put into all
positions
| 4. |
Replace the M6R Air
Temperature Door Actuator - Right and verify the M6R Air
Temperature Door Actuator - Right can be put into all
positions. |
⇒ If the M6R Air
Temperature Door Actuator - Right cannot be put into all
positions
Replace the K33 HVAC Control Module.
⇓ If the M6R Air
Temperature Door Actuator - Right can be put into all
positions
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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