GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptor

DTC B2494 02: Liftgate Handle Switch Circuit Short to Ground

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Liftgate Module B+

B153A 08, B396A 02

B153A 08, B396A 02

--

--

Liftgate Module B+

U0230 00

U0230 00

--

--

Liftgate Position Sensor 5V Reference Voltage

B153E 02

B153B 08

2

B1019 00

Full Open Signal

B153E 08

B153B 05

2

--

Object Sensors Signal

B153F 02

B153F 05

B153F 05

B153F 03, B153F 07

Open/Close Switches Signal

B2494 02

1, 2

1, 2

--

Pawl Switch Signal

B153A 00

B153A 08

B153A 00

B153A 08

Position Sensor Signal 1

B153E 08

B153E 08

B153E 05

--

Position Sensor Signal 2

B153E 08

B153A 08

B153E 05

B153E 08

Ratchet Switch Signal

B153A 00

B153A 08

B153A 00

B153A 08

Sector Switch Signal

B153A 00

B153A 00

B153A 00

B153A 08

Disengage Clutch Control

B396B 02

B396B 04

B396B 01

--

Engage Clutch Control

B396B 02

B396B 04

B396B 01

--

Liftgate Latch Cinch Control

B2495 02

B2495 04

B2495 01

--

Liftgate Latch Release Control

B2495 02

B2495 04

B2495 01

--

Liftgate Motor Close Control

B396A 02

B396A 04

B396A 01

B153E 08

Liftgate Motor Open Control

B396A 02

B396A 04

B396A 01

B153E 08

Full Open Low Reference

--

B153B 05

2

--

Liftgate Switches Low Reference

--

B153A 08

1

B153E 08

Position Sensor Low Reference

--

B153E 08

2

--

Liftgate Control Module Ground

--

U0230 00

2

--

1. Liftgate Switch Malfunction

2. Liftgate Malfunction

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

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

Connector End View Reference

Component Connector End Views

Description and Operation

Liftgate Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

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

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connectors at the liftgate close switch and liftgate handle switch.
  2. Ignition ON, verify the scan tool Liftgate Handle Sw. Status parameter is Inactive.
  3. If not the specified value, test the signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the LGM:
    • Liftgate close switch signal circuit terminal 1
    • Liftgate handle switch signal circuit terminal A
  4. Install a 3A fused jumper wire between the signal circuit terminal listed below and ground. Verify the scan tool Liftgate Handle Sw. Status parameter is Active.
  5. • Liftgate close switch signal circuit terminal 1
    • Liftgate handle switch signal circuit terminal A
    If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the LGM.
  6. Ignition OFF, connect the harness connector at the liftgate handle switch.
  7. Ignition ON, observe the scan tool Liftgate Handle Sw. Status parameter while pressing and releasing the liftgate handle switch. The parameter should change between Active and Inactive.
  8. If the parameter does not change, test or replace the liftgate handle switch.
  9. If all circuits test normal, test or replace the liftgate close switch.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate liftgate switch.
  2. Test for infinite resistance between the signal terminal and the low reference terminal listed below with the switch in the open position.
  3. • Liftgate close switch terminal 1 and terminal 2
    • Liftgate handle switch terminal A and terminal B
    If not the specified value, replace the liftgate switch.
  4. Test for less than 2 ohms between the signal terminal and the low reference terminal listed below with the switch in the closed position.
  5. • Liftgate close switch terminal 1 and terminal 2
    • Liftgate handle switch terminal A and terminal B
    If greater than the specified range, replace the liftgate switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Liftgate Outside Handle Replacement

Control Module References for LGM replacement, setup, and programming