B0428
DTC B0223, B022A, B0233, B023A, B0408, B0418, B0428, or B3531
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.
DTC Descriptor
DTC B0223 01
- Recirculate Position Command 1 Circuit Short to Battery
DTC B0223 06
- Recirculate Position Command 1 Circuit Low Voltage/Open
DTC B022A 01
- Recirculate Position Command 2 Circuit Short to Battery
DTC B022A 06
- Recirculate Position Command 2 Circuit Low Voltage/Open
DTC B0233 01
- Air Flow Control Circuit Short to Battery
DTC B0233 06
- Air Flow Control Circuit Low Voltage/Open
DTC B023A 02
- HVAC Actuators Supply Voltage Short to Ground
DTC B0408 01
- Main Temperature Control Circuit Short to Battery
DTC B0408 06
- Main Temperature Control Circuit Low Voltage/Open
DTC B0418 01
- Right Temperature Control Circuit Short to Battery
DTC B0418 06
- Right Temperature Control Circuit Low Voltage/Open
DTC B0428 01
- Rear Temperature Control Circuit Short to Battery
DTC B0428 06
- Rear Temperature Control Circuit Low Voltage/Open
DTC B3531 01
- Rear Air Flow Control Circuit Short to Battery
DTC B3531 06
- Rear Air Flow Control Circuit Low Voltage/Open
Circuit/System Description
Stepper motors are used for temperature regulation, air distribution control and recirculation door control.
With the appropriate switches at the Radio/HVAC control, the desired air temperature door position, air distribution door position and recirculation door position can be put in. The selected values are passed to the HVAC control module via the 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 appropriate door into the calculated position, in order to reach the put in temperature/position.
Conditions for Running the DTC
* Ignition ON.
* The HVAC control module is ON.
Conditions for Setting the DTC
B023A 02
The stepper motors supply output is shorted to ground.
B0223 01, B022A 01, B0233 01, B0408 01, B0418 01, B0428 01 or B3531 01
At least one control output (of four possible outputs) of the appropriate stepper motor is shorted to voltage when motor starts moving. Faults are not detected when motor is already running or target position is already reached.
B0223 06, B022A 06, B0233 06, B0408 06, B0418 06, B0428 06 or B3531 06
At least one control output (of four possible outputs) of the appropriate stepper motor is shorted to ground or open when motor starts moving. Faults are not detected when motor is already running or target position is already reached.
Action Taken When the DTC Sets
B023A 02
* The affected output will be switched off for hardware protection.
* All stepper motors are deactivated.
B0223, B022A, B0233, B0408, B0418, B0428 or B3531
* The affected output will be switched off for hardware protection.
* The affected stepper motor is deactivated.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
HVAC Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Automatic HVAC Description and Operation (Description and Operation)
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 (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Verify that DTC B023A 02 is not present.
• If DTC is present, refer to Actuator Power Supply Malfunction.
2. Verify that DTC B0223, B022A, B0233, B0408 or B0418 is not set.
• If DTC is present, refer to Actuator Malfunction.
Circuit/System Testing
Actuator Power Supply Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate actuator.
2. Ignition ON, verify that a test lamp illuminates between the 12 volt referance circuit terminal 2 and ground.
• If the test lamp does not illuminate, test the 12 volt referance circuit for a short to ground or an open/high resistance. If the circuit tests normal test or replace the K33 HVAC control module.
Actuator Malfunction
1. Ignition OFF, disconnect the X3 and X4 harness connector at the K33 HVAC Control Module.
2. Ignition ON, test for 80-200 ohm between the 12 V reference voltage circuit terminal 15 X3 and each control circuit terminal of the appropriate actuator.
• If less than the specified range, test for the 12 V reference voltage circuit and the control circuit for a short circuit. If the circuits test normal, replace the appropriate actuator.
• If greater than the specified range, test the 12 V reference voltage circuit and the control circuit for an open/high resistance. If the circuits test normal, replace the appropriate actuator.
3. If all circuits test normal, replace the K33 HVAC Control Module
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* HVAC Component Replacement Reference (Removal and Replacement)
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup, and programming