Buick Regal: DTC C0293

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 C0293

Park Brake Switch Circuit

Symptom Byte Information: Symptom Byte List.

Diagnostic Fault Information

Circuit/System Description

For an overview of the component/system, refer to: Electronic Parking Brake Description.

Conditions for Running the DTC

System Voltage=9 to 16 V

Conditions for Setting the DTC

• K20 Engine Control Module = Short to Ground - S91 Park Brake Control Switch
• K20 Engine Control Module = Short to Voltage - S91 Park Brake Control Switch
• K20 Engine Control Module = Open/High Resistance - S91 Park Brake Control Switch
• K20 Engine Control Module = Malfunction - S91 Park Brake Control Switch
• S91 Park Brake Control Switch = Activated - Greater than 90 s

Actions Taken When the DTC Sets

• Parking Brake Actuator = Disabled
• A message and/or warning indicator may be displayed to the driver.

Conditions for Clearing the DTC

• The conditions for setting the DTC no longer exist.
• A history DTC will clear after 40 consecutive malfunction-free ignition cycles.

Reference Information

Schematic Reference

Park Brake System 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

Scan Tool Reference

Control Module References

Circuit/System Verification

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

2. Press and release the switch:S91 Park Brake Control Switch.

3. Verify the scan tool parameter:Park Brake Switch=Apply & Released.

• If the parameter state does not change

Refer to: Circuit/System Testing

• Go to next step: If the parameter state changes

4. All OK.

Circuit/System Testing

1. Ignition/Vehicle - Off.

2. Disconnect the electrical connector:K17 Electronic Brake Control Module.

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

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

• Terminal 16@K17 Electronic Brake Control Module & Ground
• Terminal 32@K17 Electronic Brake Control Module & Ground
• Terminal 9@K17 Electronic Brake Control Module & Ground
• Terminal 15@K17 Electronic Brake Control Module & Ground
• Terminal 31@K17 Electronic Brake Control Module & Ground
• Terminal 8@K17 Electronic Brake Control Module & Ground
• If 1 V or greater

Repair the short to voltage on the circuit:

• Go to next step: If less than 1 V

5. Ignition/Vehicle - Off.

6. Test for infinite resistance between the test points:

• Terminal 16@K17 Electronic Brake Control Module & Ground
• Terminal 32@K17 Electronic Brake Control Module & Ground
• Terminal 9@K17 Electronic Brake Control Module & Ground
• Terminal 15@K17 Electronic Brake Control Module & Ground
• Terminal 31@K17 Electronic Brake Control Module & Ground
• Terminal 8@K17 Electronic Brake Control Module & Ground
• If less than infinite resistance

Repair the short to ground on the circuit.

• Go to next step: If infinite resistance

7. Test for less than 5 ohms between the test points: Terminal 32 & Terminal 31

• If 5 ohms or greater

1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: S91 Park Brake Control Switch
3. Test for less than 2 ohms between the test points:
   • Terminal 32@Control module harness & The other end of the circuit@Component harness
   • Terminal 31@Control module harness & The other end of the circuit@Component harness
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Replace the component: S91 Park Brake Control Switch

• Go to next step: If less than 5 ohms

8. Test for less than 5 ohms between the test points: Terminal 8 & Terminal 15

• If 5 ohms or greater

1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: S91 Park Brake Control Switch
3. Test for less than 2 ohms between the test points:
   • Terminal 8@Control module harness & The other end of the circuit@Component harness
   • Terminal 15@Control module harness & The other end of the circuit@Component harness
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Replace the component: S91 Park Brake Control Switch

• Go to next step: If less than 5 ohms

9. Test for less than 5 ohms between the test points: Terminal 9 & Terminal 16

• If 5 ohms or greater

1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: S91 Park Brake Control Switch
3. Test for less than 2 ohms between the test points:
   • Terminal 9@Control module harness & The other end of the circuit@Component harness
   • Terminal 16@Control module harness & The other end of the circuit@Component harness
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Replace the component: S91 Park Brake Control Switch

• Go to next step: If less than 5 ohms

10. Test for less than 5 ohms between the test points: Terminal 9 & Terminal 31 - Control Switch Pressed

• If 5 ohms or greater

Replace the component:S91 Park Brake Control Switch

• Go to next step: If less than 5 ohms

11. Test for less than 5 ohms between the test points: Terminal 9 & Terminal 15 - Control Switch Pressed

• If 5 ohms or greater

Replace the component: S91 Park Brake Control Switch

• Go to next step: If less than 5 ohms

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

13. Disconnect the electrical connector: S91 Park Brake Control Switch.

14. Test for less than 10 ohms between the test points: Terminal 8@S91 Park Brake Control Switch & Ground.

• If 10 ohms or greater

1. Ignition/Vehicle - Off
2. Test for less than 2 ohms between the test points:Terminal 8@S91 Park Brake Control Switch & The other end of the circuit@Ground Connection
   • If 2 ohms or greater - Repair the open/high resistance in the circuit.
   • If less than 2 ohms - Repair the open/high resistance in the ground connection.

• Go to next step: If less than 10 ohms

15. Replace the component: S91 Park Brake Control Switch.

16. Operate the vehicle within the Conditions for Running the DTC.

17. Verify the DTC does not set.

• If the DTC is set

Replace the component: K17 Electronic Brake Control Module

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

18. All OK.

Repair Instructions

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

• Parking Brake Actuator Switch Replacement
• For control module replacement, programming, and setup refer to:Control Module References

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