Immobilizer System Buick LaCrosse II

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K89 Immobilizer Control Module. It may take up to two minutes for all vehicle systems to power down.
Verify a test lamp illuminates between the low reference circuit terminal 1 and B+. If the test lamp does not illuminate Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp illuminates
Ignition ON.
Test for greater than 9 V between the ignition circuit terminal 3 and ground. If 9 V or less Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the ignition circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If greater than 9 V
Ignition ON.
Test for 10-13 V between the serial data circuit terminal 2 and ground. If less than 10 V Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the serial data circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the serial data circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If greater than 13 V Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K9 Body Control Module. If between 10-13 V
Replace the K89 Immobilizer Control Module.
Verify DTC B2955 does not set while operating the vehicle under the conditions for running the DTC. If DTC B2955 is set Replace the K9 Body Control Module. If DTC B2955 is not set
All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module or Immobilizer Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	B2955 00	B2955 00
Serial Data	B2955 00	B2955 00	B2955 00	B2955 00
Low Reference		B2955 00

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coils surrounding the ignition lock cylinder. The transponder transmits a signal to the Body Control Module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the Engine Control Module (ECM). If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.

Ignition is in the Accessory or Run position.

The BCM detects a circuit fault on the immobilizer antenna circuits.

Vehicle starting will be disabled.
The security indicator in the instrument cluster will be illuminated. A service message will be displayed in the driver information center.

A current DTC will be cleared when the condition for setting the DTC are no longer present.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K89 Immobilizer Control Module. It may take up to two minutes for all vehicle systems to power down.
Verify a test lamp illuminates between the low reference circuit terminal 1 and B+. If the test lamp does not illuminate Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If the test lamp illuminates
Ignition ON.
Test for greater than 9 V between the ignition circuit terminal 3 and ground. If 9 V or less Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the ignition circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K9 Body Control Module. If greater than 9 V
Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
Test for less than 1 V between the K89 Immobilizer Control Module serial data circuit terminal 2 and ground. If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
Replace the K89 Immobilizer Control Module.
Verify DTC B2955 does not set while operating the vehicle under the conditions for running the DTC. If DTC B2955 is set Replace the K9 Body Control Module. If DTC B2955 is not set
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module or Immobilizer Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

As part of the vehicle telematics enhanced services, a request may be sent to the Body Control Module (BCM) to disable vehicle starting. If a valid message is received by the BCM requesting that starting be disabled, the start enable message will not be sent to the Engine Control Module (ECM).

The BCM continuously monitors for this DTC.

A start disable message has been received from the telematics module.

Vehicle starting will be suspended and the security indicator will be illuminated.

A current DTC will clear when the telematics start disable request is no longer received.
A history DTC will clear after 100 ignition cycles in which the telematic start disable request is not seen.

Diagnostic Aids

DTC B302A is only an indicator that a start disable request has been received from the vehicle telematics system and does not indicate a fault in the immobilizer or telematics system.
To remove the start disable request, the vehicle account must be updated with the OnStar stolen vehicle team. This will require that a law enforcement agency or the customer contact OnStar to indicate that the vehicle has been successfully and safely recovered.
If the OnStar system has been disabled or damage during a theft attempt, the system will not be able to communicate and the start disable request will not be removed. OnStar must be functioning properly for the start disable request to be removed.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify the OnStar system is not damaged and is operating properly, with no DTCs set. If the OnStar system is damaged, inoperative, or any OnStar DTCs are set These concerns must be corrected before the start disable can be removed. If the OnStar system is not damaged and is operating properly
Press the blue OnStar button and ask the advisor to be transferred to the stolen vehicle team to verify the vehicle account has been updated.
Verify that OnStar is aware the vehicle has been recovered and that the vehicle account has been updated. If OnStar has not been notified that the vehicle has been recovered Contact the customer and advise them that for security purposes, they must contact OnStar and the law enforcement agency to update the vehicle account. If the account has been properly updated
Once the vehicle account has been updated and the start disable request has been removed, DTC B302A will transition to a history DTC. Clear the history DTC.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When learning a coded key, the Body Control Module (BCM) is placed in learn mode. DTC B3031 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the coded key is learned, learn mode will be exited and the DTC cleared. If the BCM does not exit learn mode, DTC B3031 will remain current and indicate a fault. The instrument cluster security indicator will illuminate and the driver information center will display a message.

The immobilizer system is the learn coded keys state.

The DTC will set any time the BCM enters the learn coded keys state.

The security indicator will illuminate. The driver information center will display a message.

A current DTC B3031 will be cleared upon the successful exit of learn mode.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Verify all available keys are correct for the vehicle. This can be accomplished by comparing the part number that is laser etched on the key to the part number listed in the parts catalog. If a key is not correct Replace the key If all keys are correct
Perform the Replacing Keys procedure. Refer to «Key with Integrated Transmitter Programming (without BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__key-with-integrated-transmitter-programming-without) , «Key with Integrated Transmitter Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__key-with-integrated-transmitter-programming-with) .
Verify the K9 Body Control Module learns the vehicle key and exits the learn coded key state. The scan tool Master Keys Learned parameter should increment to 1. If the K9 Body Control Module does not exit the learn coded key state after the programming attempt Replace the K9 Body Control Module If the K9 Body Control Module exits the learn coded key state after the programming attempt
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Without BTM and/or ATH/ATS

With BTM and/or ATH/ATS

When a ignition key is inserted into the key pocket/slot and the ignition mode switch is pressed, the transponder embedded in the key is energized by the immobilizer antenna exciter coil. The transponder transmits a signal to the Body Control Module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the Engine Control Module (ECM). If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.

Ignition is in the Accessory or Run position.

The BCM is unable to measure the ignition key transponder value.

Vehicle starting will be disabled.
The security indicator will illuminate. A service message will be displayed in the driver information center.

A current DTC will be cleared when the BCM detects a valid transponder value from the ignition key.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Because DTC B3055 may be caused by a malfunctioning vehicle key, it is necessary to have all available vehicle keys at the time of diagnosis. A possible scenario would be a customer leaving the vehicle with a spare key during the service visit, but the key which they use everyday, not the spare key, is the cause of the DTC. Not having all available keys in this instance would result in the customer concern not being duplicate or a misdiagnosis.
Ensure that the immobilizer control module is properly installed and fully seated. An audible and/or tactile click will indicate that the immobilizer control module is fully seated. To ensure proper transponder communication, the key must be in a specific location in relation to the immobilizer control module. If the immobilizer control module is not fully seated, transponder communication may not occur and DTC B3055 will set.
For vehicle without BTM and/or ATH/ATS, verify the customer is not attempting to turn the ignition with the vehicle key partially folded. To ensure proper transponder communication, the key must be in a specific location in relation to the immobilizer control module. Attempting to start the vehicle with the key in the ignition and partially folded will result in no transponder communication and DTC B3055 will set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Without BTM and/or ATH/ATS

Ignition ON.
Verify that DTC B1370, B1380, or B1441 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If none of the DTCs are set
Verify the scan tool Body Control Module Accessory parameter changes between Active and Inactive when turning the ignition ON and OFF. If the parameter does not change Refer to «Vehicle Will Not Change Power Mode»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures) . If the parameter changes
Verify all available keys are correct for the vehicle. This can be accomplished by comparing the part number that is laser etched on the key to the part number listed in the parts catalog. If a key is not correct Replace the appropriate key. If all keys are correct
Verify that DTC B3055 does not set while attempting to start the vehicle which each available key. If DTC B3055 sets when attempting to start the vehicle with only one of the available keys Replace the appropriate key. If DTC B3055 sets when attempting to start the vehicle with all of the available keys Replace the K89 Immobilizer Control Module. If DTC B3055 does not set
All OK.

With BTM and/or ATH/ATS

Ignition ON.
Verify that DTC B1370, B1380, or B1441 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If none of the DTCs are set
Verify the scan tool Body Control Module Accessory parameter changes between Active and Inactive when turning the ignition ON and OFF. If the parameter does not change Refer to «Power Mode Mismatch»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures) . If the parameter changes
Verify all available keys are correct for the vehicle. This can be accomplished by comparing the part number that is laser etched on the key to the part number listed in the parts catalog. If a key is not correct Replace the appropriate key. If all keys are correct
Remove the battery from each of the available vehicle keys.
Verify that DTC B3055 does not set while attempting to start the vehicle which each available key. To start the vehicle with the key battery removed, the key must be placed in the key pocket/slot. If DTC B3055 sets when attempting to start the vehicle with only one of the available keys Replace the appropriate key. If DTC B3055 sets when attempting to start the vehicle with all of the available keys Replace the K89 Immobilizer Control Module. If DTC B3055 does not set
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Immobilizer Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Without BTM and/or ATH/ATS

With BTM and/or ATH/ATS

Ignition is in the Accessory or Run position
Battery voltage is greater than 9 volts
Transponder authentication has occurred

The programed transponder type does not match the equipped system on the vehicle.
A transponder used for vehicles without BTM and/or ATH/ATS has been programmed to a vehicle with BTM and/or ATH/ATS.
A transponder used for vehicles with BTM and/or ATH/ATS has been programmed to a vehicle without BTM and/or ATH/ATS.

No action is taken.

A current DTC will be cleared when the BCM detects a programed transponder type that matches the equipped system on the vehicle.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON.
Verify all available keys/transmitters are correct for the vehicle. This can be accomplished by comparing the part number that is laser etched on the key/transmitter to the part number listed in the parts catalog. If a key/transmitter is not correct Replace the appropriate key/transmitter. If all keys/transmitters are correct
Verify the scan tool Key Part Number parameter displays a Key Part Number when turning the ignition ON with each key/transmitter. If a Key Part Number is not read Replace the appropriate key/transmitter. If a Key Part Number is read for each key/transmitter
All OK.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Without BTM and/or ATH/ATS

With BTM and/or ATH/ATS

Ignition is in the Accessory or Run position.

The transponder value measured by the BCM is incorrect or not learned to the vehicle.

Vehicle starting will be disabled.
The security indicator in the instrument cluster will be illuminated. The driver information center will display a service message.

A current DTC will be cleared when the BCM detects a valid transponder value from the ignition key.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Perform the Replacing Keys procedure. Refer to «Key with Integrated Transmitter Programming (without BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__key-with-integrated-transmitter-programming-without) , «Key with Integrated Transmitter Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__key-with-integrated-transmitter-programming-with) .
Verify the K9 Body Control Module learns the vehicle key. The scan tool Master Keys Learned parameter should increment to indicate another key has been learned. If the BCM does not learn the key Replace the key. If the BCM learns the key
All OK.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When certain modules are programmed and configured during installation, the module learns a specific environment identifier which is unique to the vehicle. The environment identifier is used to prevent the swapping modules between vehicles. The Body Control Module (BCM) is the keeper of the environment identifier. The Instrument Cluster, Electronic Brake Control Module, HVAC Control Module, Inflatable Restraint Sensing and Diagnostic Module, Engine Control Module (ECM), and Steering Column Lock Module (if equipped) each learn the environment identifier during their configuration process. During vehicle operation, each of these modules compare their environment identifier to that of the BCM. If the identifiers match, vehicle starting is allowed. If an environment identifier does not match, vehicle starting is disabled.

Ignition is in the ACCESSORY or RUN position.

An incorrect environment identifier is stored by the BCM.

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

A current DTC will be cleared when the BCM learns a correct environment identifier.

If BCM programming is not completed after BCM replacement, the environment identifier will not be learned. If DTC B389A sets immediately after the replacement and programming of a BCM, perform the programming procedure again.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Verify DTC B389A did not set immediately following the replacement and programming of the K9 Body Control Module. If the DTC set immediately after the replacement and programming of the K9 Body Control Module The immobilizer learn procedure was not properly completed. Perform the BCM 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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) . If the DTC did not set immediately after the replacement and programming of the K9 Body Control Module
Verify DTC B3902 is not set in any of the control modules listed below: K20 Engine Control Module K36 Inflatable Restraint Sensing and Diagnostic Module K17 Electronic Brake Control Module K33 HVAC Control Module P16 Instrument Cluster K60 Steering Column Lock Module (if equipped) If DTC B3902 is set in any of the modules Refer to «DTC B3902»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) . If DTC B3902 is not set in any of the modules
Perform the K9 Body Control Module immobilizer learn using Body Control Module IMMO Function with Existing Transponder or Remote Key in SPS. Refer to «Immobilizer System Component Programming (without BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) .
Verify DTC B389A does not set after programming. If the DTC sets after programming Replace the K9 Body Control Module. If the DTC does not set after programming
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Ignition is in the ACCESSORY or RUN position.

The control module's environment identifier does not match the environment identifier stored by the BCM.

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

A current DTC will be cleared when the module learns a correct environment identifier.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Perform the Programming and Setup procedure for the control module that set DTC B3902.
Verify DTC B3902 does not set after programming. If the DTC sets after programming Replace the control module that set the DTC. If the DTC does not set after programming
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Instrument Cluster, Electronic Brake Control Module, HVAC Control Module, Inflatable Restraint Sensing and Diagnostic Module, Engine Control Module, or Steering Column Lock Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Without BTM and/or ATH/ATS

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coils surrounding the ignition lock cylinder. The transponder transmits a signal to the Body Control Module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the Engine Control Module (ECM). If the learned key code does not match, the BCM will send the start disable password to the ECM.

With BTM and/or ATH/ATS

When a keyless entry transmitter is inserted into the transmitter pocket/slot and the ignition mode switch is pressed, the transponder embedded in the transmitter is energized by the immobilizer antenna exciter coil. The transponder transmits a signal to the Body Control Module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the Engine Control Module (ECM). If the learned key code does not match, the BCM will send the start disable password to the ECM.

Ignition is in the Accessory or Run position.
A valid transponder value has been read.

The transponder calculation of the challenge from the BCM does not match the BCM calculation.

Vehicle starting will be disabled.
The security indicator will illuminate. The driver information center will display a service message.

A current DTC will be cleared when a valid transponder value has been read and authenticated.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Replace the suspected inoperative or malfunctioning key.
Verify DTC B3935 does not set while operating the vehicle under the conditions for running the DTC. If the DTC is set Replace the K9 Body Control Module. If the DTC is not set
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Without BTM and/or ATH/ATS

With BTM and/or ATH/ATS

Ignition is in the Accessory or Run position.
The BCM is in the learn coded key state.

The BCM has determined the current key is not configured as a proper vehicle key.

Vehicle starting will be disabled.
The security indicator in the instrument cluster will be illuminated. A service message will be displayed in the driver information center.

A current DTC will be cleared when the BCM detects a properly configured vehicle key.
A history DTC will be cleared after 100 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Verify the engine starts with each available key. If the engine does not start with a key Replace the key. If the engine starts with all keys
All OK.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Ignition is in the ACCESSORY or RUN position.

An incorrect environment identifier is programmed or no environment identifier is programmed.

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

A current DTC will be cleared when the module learns a correct environment identifier.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Perform the Programming and Setup procedure for the control module that set DTC B3984.
Verify DTC B3984 does not set after programming. If the DTC sets after programming Replace the control module that set the DTC. If the DTC does not set after programming
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Instrument Cluster, Electronic Brake Control Module, HVAC Control Module, Inflatable Restraint Sensing and Diagnostic Module, Engine Control Module, and Steering Column Lock Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Ignition is in the ACCESSORY or RUN position.

The calculated response from the BCM does not equal the calculation performed by the ECM.

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

A current DTC will be cleared when a valid calculation is received.
A history DTC will be cleared after 40 malfunction-free ignition cycles.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no immobilizer DTCs are set in the K9 Body Control Module
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) .
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) . If the engine starts
All OK

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When learning the immobilizer data, as well as the challenge and response sequence, the Engine Control Module (ECM) is placed in learn mode. DTC P0633 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the immobilizer data and challenge/response are learned, learn mode will be exited when the engine is successfully started. If the ECM does not exit learn mode, DTC P0633 will remain current and indicate a fault.

The ECM is in learn mode.

DTC P0633 will set any time the ECM enters learn mode.

The security indicator in the instrument cluster will illuminate.

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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Note. DTC P0633 will clear upon a successful engine start. Any malfunction that will cause a no-start condition will prevent DTC P0633 from clearing. Prior to diagnosing DTC P0633, ensure that all power moding and engine control systems are operating properly and all conditions that may cause a no-start have been corrected. Do not replace the K20 Engine Control Module. Replacing the K20 Engine Control Module will not correct the no-start condition.

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»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no immobilizer DTCs are set in the K9 Body Control Module
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) .
Verify the engine starts after the K20 Engine Control Module completes the learn procedure. If the engine does not start An undiagnosed no-start condition exists. Refer to the appropriate subsection and diagnostic to correct the no-start condition. If the engine starts
All OK

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When a remote slow-down request is sent from OnStar, the vehicle communication interface 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 requested vehicle speed and the REDUCED ENGINE POWER message is displayed.

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

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.

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

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

Schematic Reference

OnStar Schematics

Connector End View Reference

Remote Vehicle Speed Limiting Description and Operation

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Perform the Stolen Vehicle Slow-Down Clear procedure with the scan tool.
Verify DTC P162B is not set. If DTC P162B is set Replace the K73 Telematics Communication Interface Control Module. If DTC P162B is not set
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Telematics Communication Interface Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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.

Ignition is in the ACCESSORY or RUN position.

The ECM receives incorrect immobilizer data from the BCM.

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no immobilizer DTCs are set in the K9 Body Control Module
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) .
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) . If the engine starts
All OK

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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.

The ECM is in learn mode.

The ECM has not learned a security code.

The security indicator in the instrument cluster will illuminate.

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.

Schematic Reference

Connector End View Reference

Description and Operation

Control Module References

Electrical Information Reference

«Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

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»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no immobilizer DTCs are set in the K9 Body Control Module
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)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , «Immobilizer System Component Programming (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) .
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. If the engine starts
All OK

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Engine Control Module replacement, programming, and setup

Symptoms - Immobilizer

IMPORTANT

The following steps must be completed before using the symptom tables.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data links.
Review the system operation in order to familiarize yourself with the system functions. Refer to «Immobilizer Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__immobilizer-description-and-operation) .

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the systems. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to OnStar Stolen Vehicle Slowdown Active in order to diagnose the symptom.

Note. This procedure is not used in Brazil.

Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When a remote slow-down request is sent from OnStar, the Telematics 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 requested vehicle speed and the REDUCED ENGINE POWER message is displayed.

Schematic Reference

OnStar Schematics

Connector End View Reference