Buick Regal: DTC C0870

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 C0870

Control Module Voltage Reference Output 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 body acceleration sensor and vertical suspension acceleration sensor. The body acceleration sensors and vertical suspension 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

C0870 03

The suspension control module detected a short to ground on the 5 V reference circuit for 1.5 s.

C0870 07

The suspension control module detected a short to voltage on the 5 V reference circuit for 1.5 s.

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 40 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. Vehicle OFF, disconnect the harness connectors at all 5 vertical body and suspension acceleration sensors.

2. Disconnect the harness connector at the K19 Suspension Control Module. Vehicle in Service Mode.

3. Test for less than 1 V between the K19 Suspension Control Module 5V reference circuit terminal 12 and ground.

• If greater than 1 V

Repair the short to voltage on the circuit.

• Go to next step: If less than 1 V

4. Vehicle OFF.

5. Test for infinite resistance between the K19 Suspension Control Module 5V reference circuit terminal 12 and ground.

• If less than infinite resistance

Repair the short to ground on the circuit.

• Go to next step: If infinite resistance

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

7. Verify the scan tool Suspension Position 5V Reference parameter is greater than 4.75 V.

• If 4.75 V or less

Replace the K19 Suspension Control Module.

• Go to next step: If greater than 4.75 V

8. Clear the DTCs.

9. Connect each vertical body and suspension acceleration sensors one at a time. Verify DTC C0870 is not set after each vertical body or suspension acceleration sensor is connected.

• If DTC C0870 is set

Replace the vertical body or suspension acceleration sensor that set DTC.

• Go to next step: If DTC C0870 is not set

10. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Front Suspension 4 Corner Leveling System Position Sensor Replacement
• Rear Suspension 4 Corner Air Leveling Position Sensor Replacement (CNQ)Rear Suspension 4 Corner Air Leveling Position Sensor Replacement (GNC)
• Control Module References for suspension control module replacement, programming, and setup

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