HVAC - Manual
DTC B0223, B0233, B023A, or B0408
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 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
Diagnostic Fault Information
Circuit/System Description
Stepper motors are used for temperature regulation, air distribution control and recirculation flap control.
With the appropriate switches at the Radio/HVAC control, the desired air temperature flap position, air distribution flap position and recirculation flap 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 flap 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, B0233 01, B023A 01, or B0408 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, B0233 06, B023A 06, or B0408 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, B0233, B023A, or B0408,
* 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 HVAC - Manual
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
Description and Operation
Manual HVAC Description and Operation HVAC - Manual
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 Testing
1. Ignition OFF, disconnect the harness connector at the appropriate door actuator, ignition ON.
2. Connect a test lamp between the B+ circuit terminal 2 and ground.
3. Verify the test lamp turns ON and OFF repeatedly when commanding the actuator ON but not OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC control module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K33 HVAC control module.
• If the test lamp turns ON and OFF
4. Connect a test lamp between each actuator harness connector terminal listed below one at a time and B+.
* Control Circuit - terminal 1
* Control Circuit - terminal 3
* Control Circuit - terminal 4
* Control Circuit - terminal 6
5. Verify the test lamp turns ON and OFF repeatedly when commanding the actuator ON but not OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, Ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If less 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF
4. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC control module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC control module.
• If the test lamp turns ON and OFF
6. Replace the appropriate HVAC door actuator.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* HVAC Component Replacement Reference Removal and Replacement
* Control Module References Control Module References for HVAC control module replacement, setup, and programming