• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Stepper Motors 12 V 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 | B0428 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 |
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 puts the mixed air flap into the calculated position, in order to reach the selected temperature.
With the temperature switches at the HVAC control, 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.
Check the following mechanical fault sources:
• | Air distribution box |
• | Air distribution hoses/air distribution ducts |
Automatic HVAC Description and Operation
⇒ | If not within the specified range, refer to DTC B0163, B0183, or B1405 |
⇒ | If not within the specified range, refer to DTC B0173, B0178, B0509, B0514 or B3933 |
⇒ | If not within the specified range, refer to DTC B0173, B0178, B0509, B0514 or B3933 |
⇒ | If not within the specified range or not change, refer to DTC B0163, B0183, or B1405 |
⇒ | If the A/C compressor cannot be activated or deactivated, refer to Air Conditioning Compressor Malfunction |
⇒ | If not the specified value, replace the A26 HVAC Control |
⇒ | If not the specified value, replace the A26 HVAC Control |
⇒ | If not the specified value, replace the A26 HVAC Control |
⇒ | If the M6L Air Temperature Actuator - Left cannot be put into all positions, replace the M6L Air Temperature Actuator - Left and verify the M6L Air Temperature Actuator - Left can be put into all positions. If the M6L Air Temperature Actuator - Left cannot be put into all positions, replace the K33 HVAC Control Module. |
Perform the Diagnostic Repair Verification