Air Temperature Malfunction
Air Temperature 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
Only C68
With the temperature switch at the HVAC controls, the desired air temperature flap position can be put in. The selected value is sent to the HVAC control module via 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 mixed air flap into the calculated position, in order to reach the selected temperature.
Only CJ2
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 put in temperature.
Diagnostic Aids
Check the following mechanical fault sources:
* Air distribution box
* Air distribution hoses/air distribution ducts
Reference Information
Schematic Reference
HVAC Schematics HVAC - Automatic
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
Automatic HVAC Description and Operation HVAC - Automatic
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 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 (CJ2) B0163DTC B0163, B0183, or B1405 (C68) B0163.
• 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 B0173.
• 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 B0173.
• 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 (CJ2) B0163DTC B0163, B0183, or B1405 (C68) B0163.
• 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 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
Only C68
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 M6L Air Temperature Door Actuator - Left and 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
3. All OK.
Only CJ2
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
1. Ignition OFF, replace the M6L Air Temperature Door Actuator - Left, ignition ON.
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
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Temperature Valve Actuator Replacement - Left Side Temperature Valve Actuator Replacement - Left Side
* Temperature Valve Actuator Replacement - Right Side Temperature Valve Actuator Replacement - Right Side
* Heater and Air Conditioning Control Replacement Heater and Air Conditioning Control Replacement
* Control Module References Control Module References for HVAC control module replacement, programming and setup