HVAC - Automatic
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 HVAC control, the desired door positions can be selected. The selected values are passed to the HVAC control module via serial data. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the stepper motors with a pulsed ground signal. The stepper motors put the appropriate door into the calculated position in order to reach the desired temperature, mode. and recirculation 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 4 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, B0233 06, or B0408 06
At least one control output (of 4 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 - Automatic
Connector End View Reference
Component Connector End Views Sunshade - Left (D61)
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 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 then OFF when commanding the appropriate actuator listed below ON but not OFF with a scan tool.
* Mode Door Position
* Air Recirculation Door Actuator Direction
* Left Temperature Door Actuator Direction
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X3 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 then OFF
4. Ignition OFF, disconnect the X3 harness connector at the K33 HVAC control module, ignition ON.
5. Test for less than 1 V between each actuator harness connector terminal listed below and ground.
* Control Circuit - terminal 1
* Control Circuit - terminal 3
* Control Circuit - terminal 4
* Control Circuit - terminal 6
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
6. Ignition OFF.
7. Test for infinite resistance between each actuator harness connector terminal listed below and ground.
* Control Circuit - terminal 1
* Control Circuit - terminal 3
* Control Circuit - terminal 4
* Control Circuit - terminal 6
• If less than infinite resistance
Repair the short to ground on the circuit.
• If Infinite resistance
8. Test for less than 2 ohms between each harness connector terminal listed below end to end.
Note: See schematic for the K33 HVAC control module terminal numbers.
* Control circuit terminal 1
* Control circuit terminal 3
* Control circuit terminal 4
* Control circuit terminal 6
• If 2 ohms or greater
Repair the open/high resistance in the circuit.
• If less than 2 ohms
9. Test or replace the actuator.
10. Verify the DTC does not set and the correct door position is achieved while operating the HVAC system under the Conditions for Running the DTC.
• If the DTC sets or door position is incorrect
Replace the K33 HVAC control module.
• If the DTC does not set and door position is correct
11. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* HVAC Component Replacement Reference HVAC Component Replacement Reference
* Control Module References Control Module References for HVAC control module replacement, programming and setup