Buick Regal: Cruise Control Malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis:Strategy Based Diagnosis
• An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC B3623

Steering Wheel Controls Distance Sensing Cruise Control Gap Up/Down Signal Circuit

DTC B3794

Cruise Control Function Request Circuit

DTC P0564

Cruise Control Multifunction Switch Circuit

DTC P0565

Cruise Control Switch Circuit

DTC P0567

Cruise Control Resume Switch Circuit

DTC P0568

Cruise Control Set Switch Circuit

DTC P056C

Cruise Control Cancel Switch Circuit

DTC P0580

Cruise Control Multifunction Switch Circuit Low Voltage

DTC P0581

Cruise Control Multifunction Switch Circuit High Voltage

DTC P0589

Cruise Control Multifunction Switch 2 Circuit

DTC P0592

Cruise Control Multifunction Switch 2 Circuit Low Voltage

DTC P0593

Cruise Control Multifunction Switch 2 Circuit High Voltage

DTC P155A

Cruise Control Switch State Undetermined

DTC P155B

Cruise Control Set/Coast Switch 2 Circuit

DTC P155C

Cruise Control Resume/Accelerate Switch 2 Circuit

DTC P162C

Vehicle Speed Limiting/Warning Switch Circuit

Symptom Byte Information: Symptom Byte List.

Diagnostic Fault Information

1.Cruise Control=Malfunction

Typical Scan Tool Data

Body Control Module-Scan Tool Parameters

Circuit/System Description

For an overview of the component/system, refer to:Cruise Control Description and Operation (Without Adaptive Cruise Control) or Cruise Control Description and Operation (With Adaptive Cruise Control).

Conditions for Running the DTC

• Ignition/Vehicle=On
• Vehicle Speed.=Greater than 40 km/h (25 MPH)
• Cruise Control=On

Frequency the DTC runs=Continuously - After the running conditions are met - For greater than 5 s

Conditions for Setting the DTC

B3623

Distance Sensing Cruise Control Follow Gap Set Circuit - Invalid Signal Received

B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581

Cruise Control Switch Circuit - Invalid Signal Received

P0589, P0592, P0593, P155B, P155C

Cruise Control Multifunction Switch 2 Circuit - Invalid Signal Received

P155A

Cruise Control Switch State Undetermined

P162C

Vehicle Speed Limiting/Warning Switch Circuit - Undetermined State

Actions Taken When the DTC Sets

• Cruise Control System Status=Disabled
• DTCs listed in the DTC Descriptor Category=Type C DTC

Conditions for Clearing the DTC

DTCs listed in the DTC Descriptor Category=Type C DTC

Reference Information

Schematic Reference

Cruise Control Wiring Schematics

Connector End View Reference

Component Connector End View Index

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Circuit/System Verification

1. Ignition - On / Vehicle - In Service Mode.

2. Verify the component works as specified:Cruise Control Switch Assembly.

3. Refer to:Body Control Module-Scan Tool Parameters in Typical Scan Tool Data.

• If a condition exists

Refer to Circuit/System Testing.

• Go to next step: If no condition exists

4. Verify the condition does not exist:Cruise Control System Status=Inhibit by ECM

• Cruise Control System Status=Inhibit by ECM

If a condition exists - Repair or replace as necessary

• Go to next step: Cruise Control System Status Inhibit by ECM

5. Verify that no DTC listed in the DTC Descriptor Category is set.

• If a related DTC is set

Refer to Circuit/System Testing.

• Go to next step: If a related DTC is not set

6. All OK.

Circuit/System Testing

Cruise Control Switch Signal

1. Ignition/Vehicle & All vehicle systems - Off.

2. Disconnect the component:K9 Body Control Module.

3. Disconnect the component:Cruise Control Switch Assembly.

4. Ignition - On / Vehicle - In Service Mode.

5. Test for less than 1 V between the test points:

• 12 V Reference circuit & Ground
• Cruise Control Switch Signal & Ground
• If 1 V or greater - Repair the short to voltage on the circuit.
• Go to next step: If less than 1 V

6. Ignition/Vehicle - Off.

7. Test for infinite resistance between the test points:

• 12 V Reference circuit & Ground
• Cruise Control Switch Signal & Ground
• If less than infinite resistance - Repair the short to ground on the circuit.
• Go to next step: If infinite resistance

8. Test for less than 2 ohms between the test points:

• 12 V Reference circuit@Component harness & The other end of the circuit@Control module harness
• Cruise Control Switch Signal@Component harness & The other end of the circuit@Control module harness
• If 2 ohms or greater - Repair the open/high resistance in the circuit.
• Go to next step: If less than 2 ohms

9. Test or replace the component:Cruise Control Switch Assembly.

10. Operate the vehicle within the Conditions for Running the DTC. Verify the DTC does not set.

• If the DTC sets

Replace the component:K9 Body Control Module

• Go to next step: If the DTC is not set

11. All OK.

Adaptive Cruise Control Gap Up/Down Switch Signal

1. Ignition/Vehicle & All vehicle systems - Off.

2. Disconnect the component:K9 Body Control Module.

3. Disconnect the component:Cruise Control Switch Assembly.

4. Ignition - On / Vehicle - In Service Mode.

5. Test for less than 1 V between the test points:

• 12 V Reference circuit & Ground
• Adaptive Cruise Control Gap Up/Down Switch Signal & Ground
• If 1 V or greater - Repair the short to voltage on the circuit.
• Go to next step: If less than 1 V

6. Ignition/Vehicle - Off.

7. Test for infinite resistance between the test points:

• 12 V Reference circuit & Ground
• Adaptive Cruise Control Gap Up/Down Switch Signal & Ground
• If less than infinite resistance - Repair the short to ground on the circuit.
• Go to next step: If infinite resistance

8. Test for less than 2 ohms between the test points:

• 12 V Reference circuit@Component harness & The other end of the circuit@Control module harness
• Adaptive Cruise Control Gap Up/Down Switch Signal@Component harness & The other end of the circuit@Control module harness
• If 2 ohms or greater - Repair the open/high resistance in the circuit.
• Go to next step: If less than 2 ohms

9. Test or replace the component:Cruise Control Switch Assembly 10. Operate the vehicle within the Conditions for Running the DTC. Verify the DTC does not set.

• If the DTC sets

Replace the component:K9 Body Control Module

• Go to next step: If the DTC is not set

11. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification.

For control module replacement, programming, and setup refer to: Control Module References.

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