Keyless Entry System and Remote Functions Buick LaCrosse II

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. 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.
2. 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.
3. «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.

Diagnostic Fault Information

Circuit/System Description

The Body Control Module communicates with the Remote Control Door Lock Receiver through the keyless entry serial data circuits. When any button on the keyless entry transmitter is pressed, the transmitter sends a signal to the Remote Control Door Lock Receiver. The Remote Control Door Lock Receiver sends a function request to the Body Control Module, depending on which button is pressed on the transmitter. The Body Control Module receives the message and performs the appropriate function.

Conditions for Running the DTC

A button is pressed on the keyless entry transmitter.

Conditions for Setting the DTC

No response is received from the Remote Control Door Lock Receiver after the Body Control Module requests information from or sends configuration commands to the Remote Control Door Lock Receiver.

Action Taken When the DTC Sets

In the case of power loss, the Remote Control Door Lock Receiver is disabled for 65 seconds. Otherwise no action is taken.

Conditions for Clearing the DTC

1. A current DTC will clear when the fault is no longer present.
2. A history DTC will clear after 40 consecutive ignition cycles without a fault present.

Reference Information

Schematic Reference

Remote Function Schematics

Component Connector End Views

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the K77 Remote Control Door Lock Receiver. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 30 ohms between the low reference circuit terminal 1 and ground. If 30 ohms or greater 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 less than 30 ohms
3. Ignition ON.
4. Test for greater than 11.5 V between the B+ circuit terminal 4 and ground. If 11.5 V or less Ignition OFF, disconnect the harness connector at the K9 Body Control Module. Test for infinite resistance between the B+ 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 B+ 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 11.5 V
5. Test for 3-6 V between the serial data circuit terminal 3 and ground. If less than 3 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 6 V Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. Test for less than 1 V between the serial data 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 3-6 V
6. Ignition OFF, disconnect the X1 and X2 harness connectors at the K9 Body Control Module, ignition ON.
7. Test for less than 1 V between the K9 Body Control Module serial data circuit terminal 27 X2 and ground. If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
8. Ignition OFF.
9. Test for infinite resistance between the K9 Body Control Module serial data circuit terminal 27 X2 and ground. If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
10. Test for less than 2 ohms between the K9 Body Control Module serial data circuit terminal 27 X2 and the K77 Remote Control Door Lock Receiver serial data circuit terminal 2. If 2 ohms or greater Repair the open/high resistance in the circuit. If less than 2 ohms
11. Replace the K77 Remote Control Door Lock Receiver.
12. Verify DTC B3101 does not set while operating the vehicle under the conditions for running the DTC. If the DTC sets Replace the K9 Body Control Module If the DTC does not set
13. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Body Control Module or Remote Control Door Lock Receiver replacement, programming and setup

1. 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.
2. 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.
3. «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 monitors the number of keyless entry transmitters programmed. Until at least one transmitter is programmed, the Body Control Module determines a malfunction condition exists.

The Body Control Module has been set up without transmitters being programmed.

No keyless entry transmitter programmed to the Body Control Module.

The keyless entry system is inoperative.

A current DTC is cleared when at least one transmitter has been programmed to the Body Control Module.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Verify that the transmitter is a correct transmitter for the vehicle. This can be accomplished by comparing the part number printed on the transmitter to the appropriate part number in the parts catalog. If the transmitter is incorrect Replace the transmitter. If the transmitter is correct
2. Program the transmitter. 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) .
3. Verify the transmitter has successfully completed the programming procedure. If the transmitter does not program successfully Replace the transmitter. If the transmitter programs successfully
4. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Key with Integrated Transmitter Programming (without BTM) , Key with Integrated Transmitter Programming (with BTM)

1. 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.
2. 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.
3. «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 communicates with the Remote Control Door Lock Receiver through the keyless entry serial data circuits. When any button on the keyless entry transmitter is pressed, the transmitter sends a signal to the Remote Control Door Lock Receiver. The Remote Control Door Lock Receiver sends a function request to the Body Control Module, depending on which button is pressed on the transmitter. The Body Control Module receives the message and performs the appropriate function.

A keyless transmitter button is pressed.

The transmitter that is sending a signal to the Remote Control Door Lock Receiver is different from those transmitters stored in the Body Control Module.

No action is taken.

1. A current DTC will clear when the fault is no longer present and the ignition switch is cycled.
2. A history DTC will clear after 40 consecutive ignition cycles without a fault present.

Schematic Reference

Remote Function Schematics

Component Connector End Views

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. With a valid and learned transmitter, press and release a button on the transmitter.
2. Verify that DTC B3106 is not set. If DTC B3106 is set Replace the K77 Remote Control Door Lock Receiver. If DTC B3106 is not set
3. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Remote Control Door Lock Receiver replacement, programming, and setup.

1. 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.
2. 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.
3. «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.

With each press of a keyless entry transmitter button, a message containing the current battery state of the transmitter is sent to the Remote Control Door Lock Receiver, along with the commanded keyless entry function. The Remote Control Door Lock Receiver sends this to the Body Control Module to perform the requested function.

A keyless transmitter button is pressed.

Three consecutive low battery signals are received from the same transmitter.

The keyless entry system is inoperative.

The DTC is cleared when a normal transmitter voltage signal is received from the transmitter that set the DTC.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Verify none of the DTCs listed below are set: DTC B3109 DTC B3110 DTC B3111 DTC B3112 DTC B3113 If any of the DTCs are set Replace the battery in the appropriate keyless entry transmitter and operate the transmitter three consecutive times. Verify the DTC does not set. If the DTC sets, replace the keyless entry transmitter. If the DTC does not set All OK. If none of the DTCs are set
2. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Key with Integrated Transmitter Programming (without BTM) , Key with Integrated Transmitter Programming (with BTM)

1. 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.
2. 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.
3. «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.

With each press of a keyless entry transmitter button, a message containing the current battery state of the transmitter is sent to the Remote Control Door Lock Receiver, along with the commanded keyless entry function. The Remote Control Door Lock Receiver sends this to the Body Control Module to perform the requested function.

A keyless transmitter button is pressed.

Three consecutive low battery signals are received from the same transmitter.

The keyless entry system is inoperative.

The DTC is cleared when a normal transmitter voltage signal is received from the transmitter that set the DTC.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Verify none of the DTCs listed below are set: DTC B310D DTC B310E DTC B310F If any of the DTCs are set Replace the battery in the appropriate keyless entry transmitter and operate the transmitter three consecutive times. Verify the DTC does not set. If the DTC sets, replace the keyless entry transmitter. If the DTC does not set All OK. If none of the DTCs are set
2. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Key with Integrated Transmitter Programming (without BTM) , Key with Integrated Transmitter Programming (with BTM)

1. 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.
2. 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.
3. «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 driver door handle antenna is located in the driver door handle assembly and is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with locked doors is approached with a keyless entry transmitter and the release handle is pulled, the keyless entry control module communicates with the driver door handle keyless entry antenna.

1. The touch pad in the driver door handle is touched within 15 minutes of last door closing.
2. The front or rear door handle on the driver side is pulled.

B3119 02

The keyless entry control module detects a short to ground on the driver door keyless entry antenna signal circuit.

B3119 05

The keyless entry control module detects a short to voltage or an open on the driver door keyless entry antenna signal circuit.

Doors will not unlock when front or rear driver handle is pulled. Doors will not lock with touch pad.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition ON.
2. Verify DTC B3122, B3123, or B3124 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
3. Refer to Circuit/System Testing below.

1. Ignition OFF, disconnect the harness connector at the T10M driver door handle keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1 V
10. Replace the T10M driver door handle keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
12. Verify DTC B3119 is not set. If DTC B3119 is set Replace the K84 keyless entry control module. If DTC B3119 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Front Side Door Outside Handle Bracket Replacement (Passive Entry Passive Start)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) , «Front Side Door Outside Handle Bracket Replacement (Base)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) - driver door handle keyless entry antenna replacement
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

1. 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.
2. 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.
3. «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 passenger front door handle antenna is located in the passenger front door handle assembly and is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with locked doors is approached with a keyless entry transmitter and the release handle is pulled, the keyless entry control module communicates with the passenger front door handle keyless entry antenna.

1. The touch pad in the passenger front door handle is touched within 15 minutes of the last change of door ajar status for any door.
2. The front or rear door handle on the passenger side is pulled.

B3120 02

The keyless entry control module detects a short to ground on the passenger front door keyless entry antenna signal circuit.

B3120 05

The keyless entry control module detects a short to B+ or an open on the passenger front door keyless entry antenna signal circuit.

Doors will not unlock when front passenger handle is pulled. Doors will not lock with passenger touch pad.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition ON.
2. Verify that DTC B3122, B3123, or B3124 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
3. Refer to Circuit/System Testing below.

1. Ignition OFF, disconnect the harness connector at the T10N passenger door handle keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1 V
10. Replace the T10N passenger door handle keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the driver release handle.
12. Verify DTC B3120 is not set. If DTC B3120 is set Replace the K84 keyless entry control module. If DTC B3120 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Front Side Door Outside Handle Bracket Replacement (Passive Entry Passive Start)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) , «Front Side Door Outside Handle Bracket Replacement (Base)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) - passenger door handle keyless entry antenna replacement
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

1. 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.
2. 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.
3. «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 rear fascia antenna is located in the rear fascia assembly and is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with locked doors is approached with a keyless entry transmitter and the exterior rear closure touch pad is pressed, the Keyless Entry Control Module communicates with the rear fascia keyless entry antenna.

1. The rear closure touch pad is pressed.
2. The scan tool activates a device control function to simulate the above action.

B3121 02

The Keyless Entry Control Module detects a short to ground on the rear fascia keyless entry antenna signal circuit.

B3121 05

The Keyless Entry Control Module detects a short to B+ or an open on the rear fascia keyless entry antenna signal circuit.

Rear closure will not open when rear closure touch pad is pressed.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition ON.
2. Verify that DTC B3122, B3123, or B3124 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
3. Refer to Circuit/System Testing below.

1. Ignition OFF, disconnect the harness connector at the T10G Keyless Entry Antenna - Rear Fascia, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 Keyless Entry 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 K84 Keyless Entry Control Module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the rear closure touch pad.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 Keyless Entry Control Module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 Keyless Entry Control Module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the rear closure touch pad.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module. Test for infinite resistance between the low reference 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 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 K84 Keyless Entry Control Module. If greater than 1 V
10. Replace the T10G Keyless Entry Antenna - Rear Fascia.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the rear closure touch pad.
12. Verify DTC B3121 is not set. If DTC B3121 is set Replace the K84 Keyless Entry Control Module. If DTC B3121 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Ignition Lock Key Transmitter Antenna Replacement - Rear Bumper Fascia»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Keyless Entry Control Module replacement, programming, and setup

1. 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.
2. 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.
3. «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 front center console antenna is located in front of the center console assembly and is used to establish low frequency communications with the keyless entry transmitter. When the driver attempts to change the ignition status of the vehicle, the keyless entry control module communicates with the front center console antenna.

1. The touch pad in the driver door or passenger door handle is touched within 15 minutes of any door ajar status changing.
2. The last door becomes closed.
3. Pressing the start/stop switch.

B3122 02

The keyless entry control module detects a short to ground on the front center console keyless entry antenna signal circuit.

B3122 05

The keyless entry control module detects a short to B+ or an open on the front center console keyless entry antenna signal circuit.

Vehicle will not detect the transmitter in some locations inside the vehicle. If the transmitter is not detected then vehicle will not change ignition modes when start/stop button is pressed.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition OFF, disconnect the harness connector at the T10J center console front keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1 V
10. Replace the T10J center console front keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
12. Verify DTC B3122 is not set. If DTC B3122 is set Replace the K84 keyless entry control module. If DTC B3122 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Ignition Lock Key Transmitter Antenna Replacement - Instrument Panel»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

1. 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.
2. 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.
3. «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 rear center console antenna is located in rear of the center console assembly and is used to establish low frequency communications with the keyless entry transmitter. When the driver attempts to change the ignition status of the vehicle, the Keyless Entry Control Module communicates with the rear center console antenna.

Pressing the ignition mode switch.

B3123 02

The Keyless Entry Control Module detects a short to ground on the rear center console keyless entry antenna signal circuit.

B3123 05

The Keyless Entry Control Module detects a short to B+ or an open on the rear center console keyless entry antenna signal circuit.

Vehicle will not detect the transmitter in some locations inside the vehicle. If the transmitter is not detected then vehicle will not change ignition modes when ignition mode switch is pressed.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition OFF, disconnect the harness connector at the T10K Keyless Entry Antenna - Center Console Rear, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 Keyless Entry 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 K84 Keyless Entry Control Module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Activate the antenna by pressing the ignition mode switch.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 Keyless Entry Control Module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 Keyless Entry Control Module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Activate the antenna by pressing the ignition mode switch.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module. Test for infinite resistance between the low reference 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 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 K84 Keyless Entry Control Module. If greater than 1 V
10. Replace the T10K Keyless Entry Antenna - Center Console Rear.
11. Activate the antenna by pressing the ignition mode switch.
12. Verify DTC B3123 is not set. If DTC B3123 is set Replace the K84 Keyless Entry Control Module. If DTC B3123 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Ignition Lock Key Transmitter Antenna Replacement - Floor Console»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Keyless Entry Control Module replacement, programming, and setup

1. 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.
2. 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.
3. «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 rear compartment antenna is located on the rear compartment floor near the seat back, centered, and is used to establish low frequency communications with the keyless entry transmitter. When the driver attempts to change the ignition status of the vehicle, the keyless entry control module communicates with the rear compartment antenna.

1. The touch pad in the driver door or passenger door handle is touched within 15 minutes of any door ajar status changing.
2. Any exterior door handle or handles is pulled.
3. The last door becomes closed.
4. Pressing the start/stop switch.

B3124 02

The keyless entry control module detects a short to ground on the rear compartment keyless entry antenna signal circuit.

B3124 05

The keyless entry control module detects a short to B+ or an open on the rear compartment keyless entry antenna signal circuit.

Vehicle will not detect the transmitter in some locations inside the vehicle. If the transmitter is not detected then vehicle will not change ignition modes when start/stop button is pressed.

1. A current DTC will clear when the conditions for setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction-free ignition cycles.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition OFF, disconnect the harness connector at the T10E rear compartment keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1 V
10. Replace the T10E rear compartment keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
12. Verify DTC B3124 is not set. If DTC B3124 is set Replace the K84 keyless entry control module. If DTC B3124 is not set
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Ignition Lock Key Transmitter Antenna Replacement - Rear Compartment»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

Symptoms - Remote Functions

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

1. Perform «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 link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Keyless Entry System Description and Operation (with BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) , «Keyless Entry System Description and Operation (without BTM)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions__keyless-entry-system-description-and-operation) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Keyless Entry System. 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) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections, wiring, terminals, connectors, poor voltage and ground connections, temperature sensitivity, electromagnetic interference, electrical noise and/or incorrect control module installed may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Garage Door Opener Malfunction»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «No Remote Detected»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
3. «Keyless Entry System Malfunction (Passive)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) , «Keyless Entry System Malfunction (Active)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
4. «Remote Vehicle Start Malfunction»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)

1. 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.
2. 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.
3. «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 universal home remote is a transmitter operating between 288 and 434 MHz. The universal home remote has three buttons that may be programmed for individual transmitter/receiver combinations to control up to three garage doors, security gates, lighting systems, etc. Each button represents a unique transmitter code section, which operates independently of the other buttons, and may be considered a separate transmitter.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Garage Door Opener Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Special Tools

EL 41540 Universal Home Remote Tester

1. Ignition OFF, disconnect the harness connector at the S25 Garage Door Opener.
2. Test for less than 10 ohms between the ground circuit terminal 3 and ground. If 10 ohms or greater Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the S25 Garage Door Opener. If the test lamp illuminates
5. Verify the LED on the S25 Garage Door Opener illuminates or flashes when each button on the S25 Garage Door Opener is pressed. If the LED does not illuminate or flash when each button is pressed Replace the S25 Garage Door Opener. If the LED illuminates or flashes when each button is pressed
6. Press and hold the two outer buttons on the S25 Garage Door Opener for greater than 30 seconds. The LED on the S25 Garage Door Opener will illuminate for 20 seconds, then begin to flash quickly for another 10 seconds. When the LED stops flashing, the system has been cleared and placed into default mode.
7. Place the EL 41540 Universal Home Remote Tester so that it is adjacent to the S25 Garage Door Opener.
8. Verify the appropriate EL 41540 Universal Home Remote Tester Indicator Lights illuminate when each button on S25 Garage Door Opener the is pressed, one at a time If the tester does not respond to each button press Replace the S25 Garage Door Opener. If the tester responds to each button press
9. Using the Hand Held Transmitter from the EL 41540 Universal Home Remote Tester kit, program a single button on the S25 Garage Door Opener. Refer to the instructions provided with the EL 41540 Universal Home Remote Tester for programming instructions.
10. Verify the Programmed indicator on the EL 41540 Universal Home Remote Tester illuminates when the programmed button on the S25 Garage Door Opener is pressed. If the Programmed indicator does not illuminate when the programmed button is pressed Replace the S25 Garage Door Opener. If the Programmed indicator illuminates when the programmed button is pressed
11. Instruct the customer to program the S25 Garage Door Opener to their device. Refer to the vehicle owners manual. If further malfunction occurs, a possible rolling code or incompatibility with the S25 Garage Door Opener will prevent programming.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Garage Door Opener replacement, programming, and setup

1. 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.
2. 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.
3. «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 transmitter authentication is requested, the front console, rear console, and rear compartment antennas simultaneously broadcast a challenge within the passenger compartment to the transmitter. If the response from the transmitter via radio frequency (RF) is a valid response, the body control module (BCM) determines there is a transmitter within the vehicle. If no response is received, the BCM determines that no transmitter is in the vehicle, and NO REMOTE DETECTED will be displayed on the DIC.

Diagnostic Aids

A low transmitter battery or radio frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

Conditions caused by external influences such are these are considered to be normal. Following this diagnostic will not diagnose an RF interference condition. If RF interference is suspected, question the customer about the conditions or location where the NO REMOTE DETECTED condition occurs.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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. This condition may be caused by low vehicle battery voltage. If the battery is not sufficiently charged (above 10 volts), the system will have difficulties detecting the fob and the NO REMOTE DETECTED message will be displayed. Correct the low battery voltage condition to eliminate this condition.

1. Verify that DTC B3119, B3120, B3121, B3122, B3123, or B3124 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
2. Lock the vehicle using the keyless entry transmitter.
3. Verify that each door and liftgate unlocks and opens by approaching the vehicle with a valid transmitter and operating their respective release handle/touch pad. If both doors and the rear compartment do not unlock/unlatch and open Refer to «Keyless Entry System Malfunction (Passive)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) , «Keyless Entry System Malfunction (Active)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) . If both doors and the rear compartment unlocks/unlatches and opens
4. Verify the vehicle starts with the transmitter located in the transmitter pocket. If the vehicle does not start Perform the «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) procedure. If the vehicle starts
5. Verify the NO REMOTE DETECTED message is not displayed on the DIC while attempting to start the vehicle, placing the keyless entry transmitter in various locations within the vehicle interior at each start attempt. The vehicle should start. If the NO REMOTE DETECTED message is displayed at any time Refer to Circuit/System Testing below. If the NO REMOTE DETECTED message is not displayed and the vehicle starts
6. Inspect for any sources of RF interference such as cell phone chargers, power supplies, etc. that would interrupt transmitter and antenna communication. If inspection does not reveal any items causing RF interference, discuss with the customer the conditions or location where the NO REMOTE DETECTED condition occurs. Discuss any devices that are normally kept in the vehicle, such as a laptop or cell phone charger, which may have been removed when the vehicle was brought in for service. It may be necessary to explain to the customer how RF interference degrades the performance of the system.

1. Ignition OFF, disconnect the harness connector at the appropriate T10 keyless entry antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1 V
10. Replace the appropriate T10 keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by pressing the ignition mode switch.
12. Verify the NO REMOTE DETECTED message is not displayed and the vehicle starts. If the NO REMOTE DETECTED message is displayed and the vehicle does not start Replace the K84 keyless entry control module. If the NO REMOTE DETECTED message is not displayed and the vehicle starts
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Ignition Lock Key Transmitter Antenna Replacement - Instrument Panel»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
2. «Ignition Lock Key Transmitter Antenna Replacement - Floor Console»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
3. «Ignition Lock Key Transmitter Antenna Replacement - Rear Compartment»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
4. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

1. 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.
2. 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.
3. «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 keyless entry transmitter is part of the vehicle key. The keyless entry system will unlock the vehicle doors or open/unlock the rear compartment when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the keyless entry transmitter sending a radio frequency to the Remote Control Door Lock Receiver, which then sends the signal to the Body Control Module (BCM). The BCM interprets the signal and activates the requested function. A low transmitter battery or radio frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

1. Unwanted or inadvertent door lock/unlock activation may be requested by the OnStar® Remote Link app. It is possible that a customer may be unaware of account usage, result in an unwanted or phantom door lock/unlock. If normal system diagnosis does results in an inability to verify the customer's concern, contact Technical Assistance Center (TAC).
2. If available, the EL 43241 Keyless Entry Tester may be used to diagnose a low transmitter battery or a malfunctioning transmitter. To test, place the transmitter on the test pad of the EL 43241 and press each transmitter button one at a time, holding each button for three seconds. If the green light on the tester does not illuminate and a tone does not sound, first replace the transmitter battery and retest. If the malfunction continues after replacing the transmitter battery, replace the transmitter.
3. When using the EL 43241 Keyless Entry Tester, first inspect the keyless entry transmitter part number to determine that it is the correct model for the vehicle. An incorrect part number transmitter may pass the test, but it will not activate the keyless entry system.
4. When the vehicle key is in the ignition, the keyless entry functions are disabled from all keyless entry transmitters.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

Special Tools

EL 43241 Keyless Entry Tester

1. Verify that the vehicle key is correct for the vehicle. This can be accomplished by comparing the part number printed on the key to the appropriate part number in the parts catalog. If the vehicle key is incorrect Replace the vehicle key. If the vehicle key is correct
2. Operate the transmitter while observing the scan tool Key Fob Function parameter for the appropriate transmitter.
3. Verify the scan tool Key Fob Function parameter corresponds with the function selected on the transmitter. If the Key Fob Function parameter does not correspond with the transmitter selection NOTE: Before replacing the transmitter, inspect the transmitter battery contacts for any corrosion or damage. If no corrosion or damage is found, replace the transmitter battery and retest before replacing the transmitter. Replace the vehicle key. Operate the new transmitter while observing the scan tool Key Fob Function parameter for the transmitter. Verify the scan tool Key Fob Function parameter correspond with the function selected on the transmitter. If the Key Fob Function parameter does not correspond with the transmitter selection, replace the K9 Body Control Module If the Key Fob Function parameter corresponds with the transmitter selection All OK. If the Key Fob Function parameter corresponds with the transmitter selection
4. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «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)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Body Control Module replacement, programming, and setup

1. 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.
2. 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.
3. «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 keyless entry antennas are used as short range low frequency transmitters. As a vehicle with locked doors is approached with a keyless entry transmitter and the release handle is pulled, the keyless entry antenna broadcasts a challenge to the transmitter in an approximate 1 meter range. If the response from the transmitter via radio frequency (RF) is valid, the locked door will be passively unlocked/unlatched and allow the door to be opened. The front doors will open with one pull of the front door handle. A low transmitter battery or radio frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

Unwanted or inadvertent door lock/unlock activation may actually be triggered by the OnStar® Remote Link Apps. Customer may be unaware of account usage, contact Technical Assistance Center (TAC) if root cause cannot be diagnosed to vehicle.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Ignition ON.
2. Verify that DTC B3119, B3120, or B3121 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
3. Verify that the transmitter is a correct transmitter for the vehicle. This can be accomplished by comparing the part number printed on the transmitter to the appropriate part number in the parts catalog. If the transmitter is incorrect Replace the transmitter. If the transmitter is correct
4. Verify the scan tool Exterior Driver Door Handle Switch, Exterior Passenger Door Handle Switch, and Trunk Lid Exterior Unlatch Switch parameters change between Active and Inactive while operating their respective release handle/touch pad. If any parameter does not change Refer to «Power Door Latch System Malfunction (Passive Entry)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) . If all of the parameters change
5. Lock the vehicle using the keyless entry transmitter.
6. Verify that each door and rear compartment unlocks and opens by approaching the vehicle with a valid transmitter and operating their respective release handle/touch pad. If both doors and the rear compartment do not unlock/unlatch and open Refer to Passive Transmitter Malfunction below. If only one door or the rear compartment does not unlock/unlatch and open Refer to Antenna Circuit Malfunction below. If both doors and the rear compartment unlocks/unlatches and opens
7. All OK.

Passive Transmitter Malfunction

1. Lock the vehicle using the keyless entry transmitter.
2. Verify that each door and rear compartment unlocks and opens by approaching the vehicle with a valid transmitter and operating their respective release handle/touch pad. If both doors and the rear compartment do not unlock/unlatch and open Replace the transmitter battery. Lock the vehicle using the keyless entry transmitter. Verify that each door and rear compartment unlocks and opens by approaching the vehicle with a valid transmitter and operating their respective release handle/touch pad. If both doors and the rear compartment do not unlock/unlatch and open, replace the transmitter. If both doors and the rear compartment unlock/unlatch and open All OK. If both doors and the rear compartment unlock/unlatch and open
3. The concern may be caused by temporary RF interference. Discuss the conditions in which the concern occurs with the customer. RF interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

Antenna Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative T10 Keyless Entry Antenna, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry 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 K84 keyless entry control module. If less than 1 V
3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
4. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate release handle/touch pad.
5. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the signal 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 signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K84 keyless entry control module. If greater than 1 V
6. Test for less than 1 V between the low reference circuit terminal 2 and ground. If 1 V or greater Ignition OFF, disconnect the harness connector at the K84 keyless entry control module, ignition ON. Test for less than 1 V between the low reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K84 keyless entry control module. If less than 1 V
7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
8. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate release handle/touch pad.
9. Verify the MAX voltage captured by the DMM is greater than 1 V. If 1 V or less Ignition OFF, disconnect the harness connector at the K84 keyless entry control module. Test for infinite resistance between the low reference 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 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 K84 keyless entry control module. If greater than 1V
10. Replace the appropriate T10 keyless entry antenna.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate release handle/touch pad.
12. Verify that the door/rear compartment unlocks and opens when the release handle/touch pad is operated. If the door/rear compartment does not unlock and open Replace the K84 keyless entry control module. If the door/rear compartment unlocks and opens
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Front Side Door Outside Handle Bracket Replacement (Passive Entry Passive Start)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) , «Front Side Door Outside Handle Bracket Replacement (Base)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
2. «Ignition Lock Key Transmitter Antenna Replacement - Rear Bumper Fascia»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions)
3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for keyless entry control module replacement, programming, and setup

1. 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.
2. 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 each diagnostic approach.
3. «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.

Remote vehicle start begins as an radio frequency message received by the Body Control Module (BCM) from a keyless entry transmitter. The BCM monitors system conditions such as content theft deterrent, hood ajar status, and body DTCs to determine if a remote vehicle start event will occur. If conditions are determined to be acceptable, the remote vehicle start message is sent to the Engine Control Module (ECM). The ECM monitors system conditions such as engine control parameters and vehicle theft deterrent to determine if engine starting will be allowed. If conditions are acceptable, the ECM will initiate engine starting. During the engine run time in a remote vehicle start attempt, before the operator enters the vehicle, the ECM may discontinue engine operation if system conditions require it or a message is received from the BCM requesting the engine be turned OFF.

1. Unwanted or inadvertent door lock/unlock activation may be requested by the OnStar® Remote Link app. It is possible that a customer may be unaware of account usage, result in an unwanted or phantom door lock/unlock. If normal system diagnosis does results in an inability to verify the customer's concern, contact Technical Assistance Center (TAC).
2. If the vehicle has a current DTC that illuminates the malfunction indicator lamp (MIL), the cause of the DTC must be diagnosed before proceeding with the Remote Vehicle Start Inoperative diagnostic.
3. The remote vehicle start system will not operate if any of the following conditions are present: A current vehicle DTC that illuminates the malfunction indicator lamp (MIL) The vehicle is in valet mode. More than 2 remote starts have been attempted. The hazard switch is in the ON position. A current hazard switch DTC is set. The vehicle hood is ajar. A current hood ajar DTC is set. Incorrect BCM software is installed and vehicle start is not enabled. The content theft deterrent system detects an alarm trigger. Excessive engine RPM Excessive coolant temperature Accelerator pedal position greater than 0 percent Vehicle not in park Vehicle theft deterrent malfunction A current automatic transmission shift lock control system DTC is set. A vehicle speed sensor signal is detected by the ECM.

Schematic Reference

Remote Function Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Keyless Entry System Description and Operation (with BTM) , Keyless Entry System Description and Operation (without BTM)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «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)
4. «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

1. Verify that the keyless entry functions operate with all available keyless entry transmitters. If any keyless entry functions do not operate properly Refer to «Keyless Entry System Malfunction (Passive)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) , «Keyless Entry System Malfunction (Active)»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions) . If all keyless entry functions operate properly
2. Verify that no Diagnostic Status History or Start Disable items are present in the scan tool BCM Remote Start Diagnostic Status History and the ECM Remote Vehicle Start Disable History parameters. If remote vehicle start disable history items are present Refer to the appropriate subsection in which the malfunction occurred. If remote vehicle start disable history items are not present
3. Verify all scan tool BCM Content Theft Trigger History parameters display None. If any BCM Content Theft Trigger History parameter does not display None Refer to «Content Theft Deterrent Malfunction»(/buick/lacrosse/ii-2009-2013/remont/door-locks-anti-theft-systems/#theft-deterrent-system) . If all BCM Content Theft Trigger History parameters display None
4. All OK.

Scheme 8

Ignition Lock Key Transmitter Antenna Replacement - Instrument Panel

Scheme 9

Ignition Lock Key Transmitter Antenna Replacement - Floor Console

Scheme 10

Ignition Lock Key Transmitter Antenna Replacement - Rear Compartment

Scheme 11

Ignition Lock Key Transmitter Antenna Replacement - Rear Bumper Fascia

Scheme 12

Keyless Entry Control Module Replacement

Scheme 13

Keyless Entry Control Module Bracket Replacement

Scheme 14

Remote Control Door Lock Receiver Replacement

Scheme 15

Garage Door Opener Transmitter Replacement

Garage Door Opener Description and Operation

The garage door opener is fixed and rolling code capable. Rolling code is a system that allows the code that the customers receiver receives from the garage door opener to change every time the garage door opener is used within operating range of the receiver. Rolling code programming requires the customer to push a learn/program button on the garage door opener receiver at their home. This button is usually located on the receiver unit under a cover (light cover) on one end of the unit. The customer must follow the garage door opener manufacturers instructions to program/learn the receiver to accept the Universal Home Remote System as an authorized opener for their unit. When the receiver and the garage door opener are initially programmed together, a code is established and a new code is created for every new transmission. The software in the receiver recognizes the garage door opener and accepts the new code.

The garage door opener is compatible with most, but not all types and brands of transmitters.

The garage door opener is a transmitter operating between 288-434 MHz. The power and range of the transmitter is limited to comply with laws governing the generation of radio frequency interference. The transmitter is programmed by the user to accept the signal generated by the user's transmitters.

The garage door opener has 3 buttons that may be programmed for individual transmitter/receiver combinations to control up to 3 garage door openers, security gates, lighting systems, etc. Each button represents a transmitter code section of the transmitter, which operates separately from any other button, and may be considered a separate transmitter. Operation consists of simply pressing a button to activate the corresponding transmitter.

Scheme 16

Keyless Entry System Description and Operation - Active

The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the door locks to unlock the vehicle. Keyless entry will lock/unlock a door or open the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver antenna that has a direct link to the body control module (BCM). The BCM interprets the signal and activates the requested function or request the appropriate ECU to activate the function via a serial data message. A low transmitter battery or radio frequency interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High radio frequency traffic areas, such as gas stations that use pay-at-the-pump radio frequency transponders, may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following features

1. Door lock/unlock
2. Rear compartment lid release
3. Illuminated entry lamps
4. Panic alarm/Vehicle locator
5. Remote vehicle start
6. Automatic window express down, if equipped. Automatic window express up, if equipped

Keyless Entry System Description and Operation - Passive

Passive keyless entry allows entry to a locked vehicle without pressing any buttons on the keyless entry transmitter. You must only have the transmitter with you. The passive entry system use low frequency antennas in several different areas on the vehicle to determine the location of the transmitter. When passively opening a locked door or the rear compartment, you must have a programmed transmitter with you in your pocket, purse, or briefcase.

When a door handle is pulled or the rear compartment touch pad is pressed, the low frequency antenna sends out a challenge to the keyless entry transmitter. Because of the low frequency, communication range is limited. The antenna will emit the challenged in a one meter range. The transmitter must be within this range to receive the challenge. The transmitter receives this challenge and emits it's response as an RF message, which is received by the remote control door lock receiver. If the response is correct, the door or rear compartment will unlock and open.

As a customer convenience feature, the keyless entry system will notify the driver if the transmitter has been left in the vehicle after exiting by chirping the vehicle horn three times. This may be turned off using vehicle personalization. Also, if the transmitter is left in the vehicle after the central door lock switch has been used to lock the vehicle, the driver door will remain unlock after exiting the vehicle. This is intended to prevent locking the transmitter in the vehicle and being unable to access it.

Keyless Entry System Description and Operation - Keyless Start

The keyless start portion of the keyless entry system allows vehicle starting, having only the transmitter as your key. The keyless start system use low frequency antennas in three different locations on the vehicle to determine the location of the transmitter. Multiple antenna are used to ensure complete coverage of the vehicle interior and rear compartment. When using the keyless start system, a programmed transmitter must be in the vehicle's interior, in the driver's pocket, purse, or briefcase.

When the ignition mode switch is pressed, the low frequency antennas emit a challenge to the keyless entry transmitter. The transmitter receives this challenge and emits it's response as an RF message, which is received by the remote control door lock receiver. If the response is correct, vehicle starting will be allowed. If RF communication is interrupted, a "No Remote Detected" message will be displayed on the DIC. In these cases, the transmitter can be placed in the transmitter pocket located in the center console, under the cupholder. The immobilizer antenna coil is located directly beneath the transmitter pocket. Placing the transmitter in the pocket will create a low powered coupling between the transmitter and immobilizer antenna, allowing communications to occur and enabling vehicle starting.

The keyless entry system has the following components

1. Keyless entry integrated key/transmitter
2. Driver and front Passenger door antennas (part of the door handle assembly)
3. Driver and front Passenger door lock sensors (part of the door handle assembly)
4. Rear fascia antenna
5. Front console antenna
6. Rear console antenna
7. Trunk antenna (rear compartment)
8. Body control module (BCM)
9. Keyless entry control module
10. Immobilizer antenna coil assembly
11. Remote control door lock receiver

Keyless Entry Transmitters

By operating any of the exterior door handles, a nearby transmitter is challenged by a keyless entry antenna. The transmitter will send an RF response to the remote control door lock receive, which communicates with the BCM. The BCM will interpret this communication and either allow entry into the vehicle or deny it.

Door Antennas

The keyless entry door antennas are used to transmit low frequency communications to the keyless entry transmitters.

The keyless entry door antennas are located in the left front and right front exterior door handle bracket. The antennas are serviced as part of the door handle assembly. The antennas are controlled by the keyless entry control module. When the exterior door handle is operated, the respective antenna will send out a challenge to the keyless entry transmitter, which begins the passive entry communications.

Rear Fascia Antenna

The rear fascia antenna is used to transmit low frequency communication to the keyless entry transmitters for entry to rear compartment.

The rear fascia antenna is located behind the rear fascia. The antenna is controlled by the keyless entry control module. When the rear compartment touch pad is pressed, the antenna sends out a challenge to the keyless entry transmitter, which begins the passive entry communications.

Front Console Passive (Instrument Panel) Antenna

This antenna is located in the lower instrument panel near the front of the center console.

The front console antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". This emits a low frequency challenge signal that is received by the keyless entry transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.

Rear Console Antenna

This antenna is located in the rear of the center console.

The rear console antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". This emits a low frequency challenge signal that is received by the keyless entry transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.

Rear Compartment Antenna

This antenna is located in the center of the rear compartment metal floor pan, near the seatback.

The rear compartment antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". This emits a low frequency challenge signal that is received by the keyless entry transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.

Immobilizer Antenna Coil Assembly

The immobilizer coil assembly is located in the center console, directly beneath the transmitter pocket. If the transmitter battery is dead, weak, or the RF signal is being interrupted, the transmitter may be placed in the pocket to create a low powered coupling between the transmitter and immobilizer antenna, allowing communications to occur and enabling vehicle starting.

The immobilizer antenna coil is controlled by the BCM. The immobilizer control module is also active when learning vehicle keys.

Keyless Entry Control Module

The keyless entry control module is a multi-function module which performs the following keyless entry system functions

1. Activating vehicle antennas for passive keyless entry functions
2. Activating vehicle antennas for keyless start functions
3. Backup control for the ECM accessory wake up and the run/crank relay
4. If equipped, controls the electronic steering column lock
5. Receiver of the door handle switch inputs and the lock sensor inputs and door open switch (not the door ajar switch)
6. Control the door unlatch motors
7. Ignition mode switch monitoring

OnStar® Remote Link

A vehicle operator may have the ability to perform some of the keyless entry functions using applications on personal devices such as smart phones. Refer to OnStar Description and Operation .

Body Control Module (BCM)

The BCM is a multi-function module that performs the following functions

1. Receive and authenticate active transmitter and keyless start signals from the remote control door lock receiver
2. Determines the functionality requested by the transmitter signal
3. Performs the function requested by the transmitter signal

Unlock Driver Door Only - Active

Momentarily press the transmitter UNLOCK button in order to perform the following functions

1. Unlock only the driver door
2. Illuminate the interior lamps for a determined length of time, or until the ignition is turned ON
3. Flash the exterior lights, if enable through personalization
4. Disarm the Content Theft Deterrent (CTD) system
5. Deactivate the CTD system when in the alarm mode

Unlock All Doors - Second Operation - Active

Momentarily press the transmitter UNLOCK button a second time, within 5 seconds of the first press, to perform the following function

Unlock the remaining doors

Unlock Driver Door Only - Passive

If enabled through personalization, approach the driver door with a valid keyless entry transmitter and pull the door handle to perform the following functions

1. Unlock and open only the driver door when door handle is operated
2. Disarm the CTD system, if equipped
3. Deactivate the CTD system when in the alarm mode

Unlock All Doors - Passive

Approach any non driver door (front or rear) or if enabled through personalization, driver door with a valid keyless entry transmitter to perform the following functions

1. Unlock all vehicle doors when the approached door handle is operated
2. Only opens door whose door handle is pulled
3. Disarm the CTD system, if equipped
4. Deactivate the CTD system when in the alarm mode

Lock All Doors - Active

Press the transmitter LOCK button to perform the following functions

1. Lock all vehicle doors
2. Immediately turn off the interior lamps
3. Flash the exterior lights, if enabled through personalization
4. Chirp the horn, if enabled through personalization
5. Arm the CTD system

Lock All Doors - Passive

Exit the vehicle (with ignition off) with the keyless entry transmitter to automatically perform the following functions, if equipped.

1. Lock all vehicle doors after a delay
2. Flash the exterior lights, if enabled through personalization
3. Chirp horn, if enabled through personalization
4. Arm the CTD system

When all doors are closed, they can also be locked from the exterior by touching the lock sensor on the outside of a front door handle while having a valid transmitter in range. This function is only active for several minutes after all doors are closed to save battery life.

If more than one keyless entry transmitter is within a vehicle and the Keyless Entry System detects that one or more transmitters have been left in the vehicle after vehicle is locked, any transmitter left within the vehicle will be temporarily deactivated until

1. A button on the deactivated key fob is pressed (will only activate the fob whose button is pressed)
2. A passive unlock of vehicle occurs
3. Change in power mode occurs

Rear Compartment Lid Release - Active

If the vehicle transaxle is in PARK or NEUTRAL and the ignition is in the OFF position, a single press of the transmitter rear compartment release button will open the rear compartment lid.

Rear Compartment Lid Release - Passive

Approach the rear of the vehicle with a valid keyless entry transmitter. Press the rear compartment lid release touch pad. The rear compartment lid will open.

If vehicle is not equipped with trunk antenna, a keyless entry transmitter left inside the truck will allow the trunk to be reopened at any time. This feature will not allow a customer to lock the transmitter in the trunk.

If vehicle has a trunk antenna and one or more transmitters are left in the trunk or interior of the vehicle, those transmitter(s) will be deactivated when the vehicle becomes locked.

Vehicle Locator/Panic Alarm/Active

A single press of the panic button performs the following functions. Some functions may be dependent on personalization settings

1. Pulses the horn three times
2. Flashes the exterior lamps three times

A press and hold of the panic button performs the following functions

1. A press and hold of the panic button performs the following functions
2. Pulses the horn and flashes the parking lamps for 30 second or until the following conditions occur: The panic button is pressed The ignition switch is turned to the RUN position with a valid key

Remote Vehicle Start/Active

The remote vehicle start function allows engine starting while not in the vehicle. It also allows the vehicle HVAC system and other vehicle systems to enable, providing a comfortable vehicle upon entry. Remote vehicle start functions have an operating range of up to 195 feet, depending on conditions. The remote vehicle start sequence begins by pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the keyless entry transmitter. The turn signal lamps will illuminate to indicate the vehicle has received the remote start request. Each time a remote vehicle start is performed, the vehicle doors are locked, however they may then be unlocked/locked with the transmitter or vehicle key at any time. Once activated, the engine is allowed to run for 10 minutes. The remote vehicle start time may be extended by an additional 10 minute by again pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the transmitter. This feature is called a remote vehicle start continue and allows a maximum of 20 minutes of engine running. If the remote vehicle start continue is performed at 7 minutes into the initial 10 minute time-out, a total of 17 minutes of engine running would occur. The remote vehicle start event may be suspended at any time by pressing only the remote vehicle start button on the transmitter or by entering the vehicle and turning ON the hazard lamps.

In between ignition cycles, only two remote vehicle start events may occur or be attempted. Once two events or attempts have been made, future remote vehicle start events will be suspended until the vehicle is started using the ignition.

Enable/Disable Remote Vehicle Start/Active

Using the driver information center, remote vehicle start may be enabled or disabled as a part of vehicle personalization. Refer to the vehicle owners manual for more information.

Hood Ajar Switch/Active

The hood switch provides status of the hood to the BCM for remote vehicle start purposes. The switch is integrated into the hood latch assembly. The hood ajar switch provides 2 separate inputs to the BCM. These separate inputs allow the BCM to actively monitor for a hood ajar switch fault.

Remote Vehicle Start Circuit Description/Active

The BCM receives a signal from the keyless entry transmitter indicating a remote vehicle start request. The BCM uses the following inputs to verify the system is ready for a remote vehicle start event

1. Vehicle is not in valet mode
2. All vehicle doors are closed
3. Rear compartment lid is not ajar
4. The hood is closed
5. The doors are locked
6. The hazard switch is OFF
7. Battery reconnect has not occurred
8. Vehicle power mode is correct.

When the BCM determines all conditions meet those required for an remote vehicle start event, a message is sent via serial data to the ECM. The ECM relies on the remote vehicle start message from the BCM to enable remote vehicle start when the crank request signal is received. If the ECM does not receive a valid remote vehicle start message, it will not ground the control circuit of the crank relay and start the engine. While the ECM is in remote vehicle start mode it will cut fuel to the engine if any of the following additional conditions occur

1. Vehicle speed is greater than 0.
2. Transmission is not in P.
3. Excessive engine coolant temperature
4. Low oil pressure
5. The malfunction indicator lamp (MIL) is commanded ON.
6. Engine crank time is greater than 30 seconds.
7. Excessive engine speed.
8. Accelerator pedal position too high.
9. Remote start timer equals 0.
10. Immobilizer system indicates a theft attempt

Keyless Entry Personalization

Vehicle lock/unlock functions and remote vehicle start settings may be personalized for the vehicle. For functional descriptions and programming instructions, refer to the vehicle owners manual.

Keyless Entry System Description and Operation (without BTM)

The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the door locks to unlock the vehicle. Keyless entry will lock/unlock the vehicle doors or open the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the Remote Control Door Lock Receiver antenna that has a direct link to the Body Control Module (BCM). The BCM interprets the signal and activates the requested function or request the appropriate control module to activate the function via a serial data message. A low transmitter battery or radio frequency interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High radio frequency traffic areas, such as gas stations that use pay-at-the-pump radio frequency transponders, may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following features

1. Door lock/unlock
2. Liftgate lock/unlock, if equipped
3. Trunk release, if equipped
4. Power liftgate, if equipped
5. Vehicle locator/Panic alarm
6. Remote vehicle starting, if equipped

The keyless entry system has the following components

1. Keyless entry transmitters
2. Body Control Module
3. Remote Control Door Lock Receiver

Note. When the vehicle key is in the ignition, keyless entry functions from all keyless entry transmitter are disabled.

The keyless entry transmitters are used to perform various entry functions while away from the immediate are of the vehicle. Keyless entry functions may work at up to 20 m (65 ft) away from the vehicle. Ambient conditions may affect the performance of the keyless entry transmitter and reduce the range at which keyless entry functions operate. Up to eight transmitters may be programmed to a single vehicle. The keyless entry transmitter is an integral part of the vehicle key.

OnStar® Remote Link (if equipped)

A vehicle operator may have the ability to perform some of the keyless entry functions using applications on personal devices such as a smart phone. Unwanted or inadvertent door lock/unlock activation may be requested by the OnStar® Remote Link app. It is possible that a customer may be unaware of account usage, result in an unwanted or phantom door lock/unlock. If normal system diagnosis does results in an inability to verify the customer's concern, contact Technical Assistance Center (TAC).

The BCM is a multifunction module that operates the keyless entry system. When an radio frequency message is received from a keyless entry transmitter, the BCM interprets this signal and performs the specific function, i.e. door lock, door unlock, or vehicle locate.

Remote Control Door Lock Receiver

The Remote Control Door Lock Receiver acts as an antenna for the keyless entry system and communicates with the BCM through a dedicated serial data link. When a button is pressed on a keyless entry transmitter, the Remote Control Door Lock Receiver receives this signal and sends the request to the BCM. The BCM interprets the signal and performs the specific function, i.e. door lock, door unlock, or vehicle locate.

Unlock Doors

Momentarily press the transmitter UNLOCK button in order to perform the following functions

1. Unlock only the driver door or all doors and liftgate (if equipped). This is customized through the DIC.
2. Illuminate the interior lamps for a determined length of time or until the ignition is turned ON.
3. Flash the exterior lights; this is customized through the DIC.
4. Disarm the content theft deterrent system, if equipped.
5. Deactivate the content theft deterrent system when in the alarm mode.

Lock All Doors

Press the transmitter LOCK button to perform the following functions

1. Lock all vehicle doors.
2. Immediately turn OFF the interior lamps.
3. Flash the exterior lights and/or sound the horn; this is customized through the DIC.
4. Arm the content theft deterrent system.

Trunk Release, if equipped

Press the trunk release button on the transmitter to open the trunk.

Power Liftgate, if equipped

Press and hold the power liftgate button to perform the following functions

1. Open or close the liftgate using the power liftgate function.
2. Flash the tail lamps.
3. Sound the interior power liftgate chime.

Vehicle Locator/Panic Alarm

A single press of the panic button performs the following functions. Some functions may be dependent on personalization settings

1. Pulse the horn three times.
2. Flash the exterior lamps three times.

A press and hold of the panic button performs the following functions

1. Illuminate the interior lamps.
2. Pulse the horn and flash the exterior lamps for 30 seconds or until the following conditions occur: The panic button is pressed. The ignition switch is turned to the RUN position with a valid key.

Remote Vehicle Start, if equipped

The remote vehicle start function allows engine starting while not in the vehicle. It also allows the vehicle HVAC system and other vehicle systems to enable, providing a comfortable vehicle upon entry. The remote vehicle start sequence begins by pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the keyless entry transmitter. The turn signal lamps will illuminate to indicate the vehicle has received the remote start request. Each time an remote vehicle start is performed, the vehicle doors are locked, however they may then be unlocked/locked with the transmitter or vehicle key at any time. Once activated, the engine is allowed to run for 10 minutes. The remote vehicle start time may be extended by an additional 10 minutes by again pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the transmitter. This feature is called a remote vehicle start continue and allows a maximum of 20 minutes of engine running. If the remote vehicle start continue is performed at seven minutes into the initial 10 minute time-out, a total of 17 minutes of engine running would occur. The remote vehicle start event may be suspended at any time by pressing only the remote vehicle start button on the transmitter or by entering the vehicle and pressing the hazard lamp switch.

In between ignition cycles, only two remote vehicle start events may occur or be attempted. Once two events or attempts have been made, future remote vehicle start events will be suspended until the vehicle is started using the ignition.

Enable/Disable Remote Vehicle Start

Using the driver information center, remote vehicle start may be enabled or disabled as a part of vehicle personalization. Refer to the vehicle owners manual for more information.

Hood Ajar Switch

The hood switch provides status of the hood to the BCM for remote vehicle start purposes. The switch is integrated into the hood latch assembly.

Remote Vehicle Start Circuit Description

The BCM receives a signal from the keyless entry transmitter indicating a remote vehicle start request. A message is then sent to the BCM which determines if a crank request message will be sent to the ECM to allow engine starting. To determine if conditions are correct for an remote vehicle start event, the BCM will ensure the following conditions are met

1. A valid hood ajar switch closed signal is present.
2. The doors are locked.
3. The hazard switch is OFF.
4. The vehicle power mode is correct.
5. No content theft deterrent alarm triggers are present.

When the BCM determines all conditions meet those required for an remote vehicle start event, a message is sent via serial data to the ECM. The ECM relies on the remote vehicle start message from BCM to enable remote vehicle start when the crank request signal is received. If the ECM does not receive a valid remote vehicle start message, it will not attempt to start the engine. While the ECM is in remote vehicle start mode it will suspend engine operation if any of the following additional conditions occur

1. Vehicle speed is greater than 0.
2. Transmission is not in PARK.
3. Excessive engine coolant temperature
4. Low oil pressure
5. The malfunction indicator lamp (MIL) is commanded ON.
6. Engine crank time is greater than 30 seconds.
7. Excessive engine speed
8. Accelerator pedal position too high
9. Remote start timer equals 0.
10. Immobilizer system indicates tamper

Vehicle lock/unlock functions and remote vehicle start remote vehicle start settings may be personalized. For functional descriptions and personalization instructions, refer to the vehicle owners manual.

Special Tools

Illustration Tool Number/Description EL 43241 Keyless Entry Tester

Scheme 17

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Key with Integrated Transmitter Programming (without BTM)
• Key with Integrated Transmitter Programming (with BTM)
• Diagnostic Trouble Code (DTC) List - Vehicle
• Front Side Door Outside Handle Bracket Replacement (Passive Entry Passive Start)
• Checking Aftermarket Accessories
• Content Theft Deterrent Malfunction
• Front Floor Console Side Cover Replacement - Right Side
• Front Floor Panel Carpet Replacement
• Rear Bumper Fascia Replacement
• Fastener Caution
• Garage Door Opener Programming and Setup
• OnStar Description and Operation
• DTC B3101
• Keyless Entry System Description and Operation (without BTM)
• Garage Door Opener Description and Operation