Buick Regal: DTC C018A, C019A, or C027F

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 C018A

Yaw Rate Signal

DTC C019A

Yaw Rate 2 Signal

DTC C027F

Longitudinal Acceleration Signals 1 - 2 Not Plausible

For symptom byte information refer to Symptom Byte List.

Circuit/System Description

The yaw rate, lateral acceleration and longitudinal acceleration sensors are combined into one multi-axis acceleration sensor, internal to the inflatable restraint sensing and diagnostic module. The multi-axis acceleration sensor communicates with the electronic brake control module via serial data. The electronic brake control module activates the stability control function depending on the multi-axis acceleration sensor input. The inflatable restraint sensing and diagnostic module uses the multi-axis acceleration sensor to determine if the vehicle is in a roll over or near collision incident.

Conditions for Running the DTC

• Ignition ON begins the initialization of the brake system power-up self test.
• Drive the vehicle at speeds greater than 16 km/h (10 MPH) to complete the active brake system test.

Conditions for Setting the DTC

C018A

The lateral acceleration signal 2 is out of the specified range.

C019A

The yaw rate signal 2 is out of the specified range.

C027F

Correlation concern between longitudinal acceleration signals 1 and 2.

Action Taken When the DTC Sets

• The traction control Off indicator turns ON.
• The traction/stability control indicator turns ON.
• A Traction Control Off message may be displayed.
• A Service Stabilitrak message may be displayed.
• The electronic brake control module disables the traction control and the stability control for the duration of the ignition cycle.

Conditions for Clearing the DTC

• The DTC clears when the diagnostic runs and passes.
• The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Antilock Brake System Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

ABS 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 DTC B101D is not set current or history in the K36 Inflatable Restraint Sensing and Diagnostic Module.

• If DTC B101D is set current or history in the K36 Inflatable Restraint and Sensing Diagnostic Module

Replace the K36 Inflatable Restraint Sensing and Diagnostic Module.

• Go to next step: If DTC B101D is not set current or history in the K36 Inflatable Restraint and Sensing Diagnostic Module

2. Verify DTC C0186, C0196, or C0287 is not set in the K36 Inflatable Restraint Sensing and Diagnostic Module.

• If any of the DTCs are set

Perform the Vehicle Yaw Sensor Learn.

• Go to next step: If none of the DTCs are set

3. Verify DTC C0187, C0196, or C0287 is not set in the K17 Electronic Brake Control Module.

• If any of the DTCs are set

1. Replace the K36 Inflatable Restraint Sensing and Diagnostic Module.
2. Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
   • If the DTC sets, replace the K17 Electronic Brake Control Module.
   • Go to next step: If the DTC does not set
3. All OK.

• Go to next step: If none of the DTCs are set

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Control Module References for Electronic Brake Control Module replacement, programming and setup

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