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 Descriptors

DTC B2495 01: Endgate/Liftgate Latch Control Circuit Short to Battery

DTC B2495 02: Endgate/Liftgate Latch Control Circuit Short to Ground

DTC B2495 04: Endgate/Liftgate Latch Control Circuit Open Circuit

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 latch motor is a bi-directional motor and cinch or unlatch operation is the result of the direction of the motor rotation. The liftgate module (LGM) controls the latch motor through the control circuits by supplying power and ground in the appropriate polarity. The motor control circuits are monitored by the LGM prior to activation for a high or low condition and during motor operation for an insufficient current flow condition.

Conditions for Running the DTC

The system voltage is 9-16 volts.

Conditions for Setting the DTC

B2495 01

The LGM detects a short to voltage in the liftgate latch motor open control circuit or the liftgate latch motor close control circuit.

B2495 02

The LGM detects a short to ground in the liftgate latch motor open control circuit or the liftgate latch motor close control circuit.

B2495 04

The LGM detects an open/high resistance in the liftgate latch motor open control circuit or the liftgate latch motor close control circuit.

Action Taken When the DTC Sets

The liftgate latch 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, command the liftgate to OPEN and CLOSE with the scan tool. The liftgate latch assembly should release the liftgate allowing the liftgate to open.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
  2. Test for less than 5 ohms between the control circuit terminal 1 and ground.
  3. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the LGM.
  4. Test for less than 5 ohms between the control circuit terminal 3 and ground.
  5. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the LGM.
  6. Connect a test lamp between control circuit terminal 1 and ground.
  7. Install a jumper wire between the low reference circuit terminal 2 and ground.
  8. Ignition ON, command the liftgate to OPEN by pressing and releasing the liftgate close switch. The test lamp should illuminate while commanding the OPEN state.
  9. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the LGM.
    If the test lamp is always ON, test the control circuit for a short to voltage, if the circuit tests normal, replace the LGM.
  10. Ignition OFF, connect a test lamp between the control circuit terminal 3 and ground.
  11. Connect a 3A fused jumper wire between the signal circuit terminal 6 and ground.
  12. Ignition ON, command the liftgate to CLOSE by pressing and releasing the liftgate close switch. The test lamp should illuminate while commanding the CLOSE state.
  13. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the LGM.
    If the test lamp is always ON, test the control circuit for a short to voltage, if the circuit tests normal, replace the LGM.
  14. If all circuits test normal, test or replace the liftgate latch assembly.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the liftgate latch.
  2. Install a 20A fused jumper wire between the control terminal 1 and 12 volts. Momentarily install a jumper wire between the control terminal 3 and ground. The liftgate latch should perform the CINCH or RELEASE function.
  3. If the function does not perform as specified, replace the liftgate latch.
  4. Reverse the jumper wires; the liftgate should perform the RELEASE or CINCH function.
  5. If the function does not perform as specified, replace the liftgate latch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for LGM replacement, setup and programming