Buick Regal: DTC C0670 or C0675

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0670

Left Front Acceleration Sensor Circuit

DTC C0675

Right Front Acceleration Sensor Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

Circuit/System Description

The suspension control module supplies a 5 V reference voltage and a low reference to each vertical wheel acceleration sensor. The vertical wheel acceleration sensors supply a signal of 0.5 - 4.5 V to the suspension control module.

Conditions for Running the DTC

System voltage is between 9 - 16 V.

Conditions for Setting the DTC

C0670 02 and C0675 02

The signal voltage is less than 0.5 V for 1.5 s.

C0670 05 and C0675 05

The signal voltage is greater than 4.5 V for 1.5 s.

C0670 0A and C0675 0A

• The number of signal changes is less than specified value for 2.5 s.
• Vehicle speed is greater than 30 km/h (19 MPH).

Action Taken When the DTC Sets

• The electronic suspension control is disabled for the duration of the ignition cycle.
• The driver information center displays the SERVICE SUSPENSION SYSTEM message.

Conditions for Clearing the DTC

• A present DTC will clear on the next consecutive malfunction-free ignition cycle.
• A history DTC will clear after 41 consecutive malfunction-free ignition cycles.

Reference Information

Schematic Reference

Electronic Suspension Control Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Description and Operation

Electronic Suspension Control Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition ON, verify that DTC C0870 is not present.

• If the DTC C0870 is present, refer to DTC C0870
• Go to next step: If the DTC C0870 is not present

2. Vehicle OFF and all vehicle systems OFF. Disconnect the harness connector at the appropriate B161 Vertical Suspension Acceleration Sensor. It may take up to 2 min for all vehicle systems to power down.

3. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.

• If 10 Ω or greater

1. Vehicle OFF, disconnect the harness connector at the K19 Suspension Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K19 Suspension Control Module.

• Go to next step: If less than 10 Ω

4. Vehicle in Service Mode.

5. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than 4.8 V

1. Vehicle OFF, disconnect the harness connector at the K19 Suspension Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the 5 V reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K19 Suspension Control Module.

• If greater than 5.2 V

1. Vehicle OFF, disconnect the harness connector at the K19 Suspension Control Module, vehicle in Service Mode.
2. Test for less than 1 V between the 5 V reference circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K19 Suspension Control Module.

• Go to next step: If within 4.8 - 5.2 V

6. Vehicle OFF, disconnect the harness connector at the K19 Suspension Control Module, vehicle in Service Mode.

7. Test for less than 1 V between the appropriate B161 Vertical Suspension Acceleration Sensor signal circuit terminal 3 and ground.

• If greater than 1 V

Repair the short to voltage on the circuit.

• Go to next step: If less than 1 V

8. Vehicle OFF.

9. Test for infinite resistance between the appropriate B161 Vertical Suspension Acceleration Sensor signal circuit terminal 3 and ground.

• If less than infinite resistance

Repair the short to ground on the circuit.

• Go to next step: If infinite resistance

10. Test for less than 2 Ω between the appropriate B161 Vertical Suspension Acceleration Sensor signal circuit terminal 3 and the K19 Suspension Control Module signal circuit listed below.

• Terminal 10
• Terminal 11
• If 2 Ω or greater

Repair the open/high resistance in the circuit.

• Go to next step: If less than 2 Ω

11. Replace the appropriate B161 Vertical Suspension Acceleration Sensor.

12. Verify the DTC does not set while operating the vehicle under Conditions for Running the DTC.

• If the DTC sets

Replace the K19 Suspension Control Module.

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

13. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Front Suspension 4 Corner Leveling System Position Sensor Replacement
• Control Module References for suspension control module replacement, setup and programming

DTC C0720

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC C0720 71

Engine Torque Management Feedback Signal Invalid Data

Circuit/System Description

The suspension control module receives high speed controller area network (CAN) message inputs from the engine control module (ECM) identifying the actual engine torque. The suspension control module utilizes this signal to control the vehicle ride characteristics.

Conditions for Running the DTC

System voltage is between 9 - 16 V.

Conditions for Setting the DTC

The suspension control module received invalid serial data from the ECM.

Action Taken When the DTC Sets

The electronic suspension control is disabled for the duration of the ignition cycle.

Conditions for Clearing the DTC

• A present DTC will clear on the next consecutive malfunction-free ignition cycle.
• A history DTC will clear after 40 consecutive malfunction-free ignition cycles.

Reference Information

Schematic Reference

Electronic Suspension Control Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

Electronic Suspension Control Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Verify that no DTCs are present in the ECM.

• If any DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

• Go to next step: If no DTCs are set

2. Replace the K19 Suspension Control Module and verify the DTC does not reset.

• If the DTC sets

Replace the K20 Engine Control Module.

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

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, setup and programming.

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