Buick Regal: DTC P162B

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 P162B

Remote Vehicle Speed Limiting Signal Message Counter Incorrect

Circuit/System Description

When a remote slow-down request is sent from OnStar, the vehicle communication interface control module sends a serial data message to the engine control module (ECM) indicating that reduced vehicle speed has been requested. Once the request is active, the ECM begins reducing engine torque to match the requested vehicle speed and the REDUCED ENGINE POWER message is displayed.

Conditions for Running the DTC

• The engine run time is greater than 5 s
• A remote slow-down request is sent from OnStar

Conditions for Setting the DTC

• The VIN embedded in the slow-down request does not match the VIN stored in the ECM.
• The rolling code counter embedded in the slow-down request does not increment for ten consecutive messages.

Action Taken When the DTC Sets

• ECM ignores all reduced vehicle speed request messages from the vehicle communication interface module.
• The ECM stores DTC P162B in history.

Conditions for Clearing the DTC

• The condition responsible for setting the DTC no longer exists.
• A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

OnStar/Telematics Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

Remote Vehicle Speed Limiting 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 Verification

1. Verify the vehicle is equipped with OnStar (RPO UE1) and DTC P162B is set

• If the vehicle is not equipped with OnStar (RPO UE1) and DTC P162B is set

Replace the ECM.

• Go to next step: If the vehicle is equipped with OnStar (RPO UE1) and DTC P162B is set

2. Perform the Remote Vehicle Speed Limiting Reset procedure with the scan tool.

3. Verify DTC P162B is not set.

• If DTC P162B is set

1. Reprogram the ECM. Refer to Control Module References.
2. Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
   • If the DTC sets, replace the ECM. If the DTC continues to set after ECM replacement, replace the vehicle communication interface module.
   • Go to next step: If the DTC does not set
3. All OK.

• Go to next step: If DTC P162B is not set

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for telematics communication interface control module or engine control module replacement, programming, and setup.

DTC P1631

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 P1631

Immobilizer Fuel Enable Signal Not Correct

Circuit/System Description

The body control module (BCM) sends the pre - release information to the engine control module (ECM) via the serial data circuit. The ECM then sends a challenge to the BCM. Both the ECM and BCM perform a calculation on this challenge. If the calculated response from the BCM equals the calculation performed by the ECM, the ECM will allow vehicle starting. The BCM follows this action by sending the remaining immobilizer data to the ECM. If the immobilizer data sent by the BCM matches that stored by the ECM, the ECM will allow the engine to remain running.

Conditions for Running the DTC

Ignition is in the ACCESSORY or RUN position.

Conditions for Setting the DTC

The ECM receives incorrect immobilizer data from the BCM.

Action Taken When the DTC Sets

• The security indicator in the instrument cluster will illuminate.
• Vehicle starting will be disabled.

Conditions for Clearing the DTC

• A current DTC will be cleared when correct immobilizer data is received.
• A history DTC will be cleared after 40 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Immobilizer Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

Immobilizer 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 Verification

1. Verify there are no immobilizer DTCs set in the K9 Body Control Module.

• If any immobilizer DTCs are set in the K9 Body Control Module

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

• Go to next step: If no immobilizer DTCs are set in the K9 Body Control Module

2. Perform the K9 Body Control Module immobilizer learn using the body control module IMMO Function with Existing Transponder or Remote Key in SPS. Refer to Immobilizer System Component Programming (without BTM)Immobilizer System Component Programming (with BTM).

3. Verify the engine starts after the K9 Body Control Module completes the learn procedure.

• If the engine does not start

Perform the K20 Engine Control Module immobilizer learn using the engine control module IMMO Learn in SPS. Refer to Immobilizer System Component Programming (without BTM)Immobilizer System Component Programming (with BTM).

• Go to next step: If the engine starts

4. All OK.

DTC P1649

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 P1649

Immobilizer Security Code Not Programmed

Circuit/System Description

When learning the security code, as well as the challenge and response sequence, the engine control module (ECM) is placed in learn mode. Once the security code and challenge/response are learned, learn mode will be exited when the engine is successfully started.

Conditions for Running the DTC

The ECM is in learn mode.

Conditions for Setting the DTC

The ECM has not learned a security code.

Action Taken When the DTC Sets

The security indicator in the instrument cluster will illuminate.

Conditions for Clearing the DTC

• A current DTC will be cleared upon a successful engine start after exit of learn mode.
• A history DTC will be cleared after 100 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Immobilizer Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

Immobilizer 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

Circuit/System Verification

1. Verify there are no immobilizer DTCs set in the K9 Body Control Module.

• If any immobilizer DTCs are set in the K9 Body Control Module

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

• Go to next step: If no immobilizer DTCs are set in the K9 Body Control Module

2. Perform the K20 Engine Control Module immobilizer learn using the engine control module IMMO Learn in SPS. Refer to Immobilizer System Component Programming (without BTM)Immobilizer System Component Programming (with BTM).

3. Verify the engine starts after the K20 Engine Control Module completes the learn procedure.

• If the engine does not start

Replace the K20 Engine Control Module.

• Go to next step: If the engine starts

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

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