Power Liftgate

DTC B2494 (Power Liftgate)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC B2494 02
- Liftgate Handle Switch Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

The power liftgate button and exterior liftgate handle switch are parallel circuits and provide a single input to the liftgate module (LGM). The liftgate switches are supplied voltage and share a common low reference circuit from the LGM. When the switch contacts close, the LGM detects the voltage drop and commands the liftgate to open or close depending upon the position of the liftgate at the time.

Conditions for Running the DTC

The system voltage is 9-16 volts.

Conditions for Setting the DTC

The Liftgate Open/Close Signal circuit is active for greater than 10 minutes.

Action Taken When the DTC Sets

The liftgate open and close functions from the liftgate switches will be inoperative.

Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 ignition cycles.

Diagnostic Aids

Important: Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power (Procedures) for the appropriate procedure.


Whenever the LGM loses power or is disconnected, the ignition must be cycled OFF then ON in order to reactivate the LGM.

Reference Information
Schematic Reference

Liftgate Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Liftgate Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Liftgate Handle Sw. Status parameter while pressing and releasing the liftgate handle and liftgate close switches. The value should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the liftgate handle and liftgate close switches.
2. Ignition ON, verify the scan tool Liftgate Handle Sw. Status parameter is Inactive.

• If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the LGM.

3. Ignition OFF, connect the harness connector at the liftgate close switch.
4. Ignition ON, observe the scan tool Liftgate Handle Sw. Status parameter while pressing and releasing the liftgate close switch, the parameter should change between Active and Inactive.

• If the value does not change, test or replace the liftgate close switch.

5. If all circuits test normal, test or replace the liftgate handle switch.

Component Testing

Liftgate Handle Switch
1. Ignition OFF, disconnect the harness connector at the liftgate handle switch.
2. Test for infinite resistance between the signal terminal A and the low reference terminal B with the switch in the open position.

• If not the specified value, replace the liftgate handle switch.

3. Test for less than 2 ohms between the signal terminal A and the low reference terminal B with the switch in the closed position.

• If greater than the specified range, replace the liftgate handle switch.

Liftgate Close Switch
1. Ignition OFF, disconnect the harness connector at the liftgate close switch.
2. Test for infinite resistance between the signal terminal D and the low reference terminal A with the switch in the open position.

• If not the specified value, replace the liftgate close switch.

3. Test for less than 2 ohms between the signal terminal D and the low reference terminal A with the switch in the closed position.

• If greater than the specified range, replace the liftgate close switch.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Liftgate Release Switch Replacement (Except Avalanche and Escalade EXT) (Liftgate Release Switch Replacement (Except Avalanche and Escalade EXT))
* Control Module References (Programming and Relearning) for liftgate control module replacement, programming and setup