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 B153E 02: Liftgate Position Sensor Signal Circuit Short to Ground

DTC B153E 05: Liftgate Position Sensor Signal Circuit Short to Battery or Open

DTC B153E 08: Liftgate Position Sensor Signal Circuit Signal Invalid

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Liftgate Module B+

B396A 02, B153A 08

B396A 02, B153A 08

--

--

Liftgate Position Sensor 5V Reference Voltage

2

B153E 08

2

--

Full Open Signal

B153B 02

B153B 05

2

--

Liftgate Disable Signal

1, 2

1

1

--

Liftgate Open Signal

1

1

1

--

Object Sensors Signal

B153F 05

B153F 05

B153F 07

--

Open/Close Switches Signal

B2494 02

1, 2

1, 2

--

Pawl Switch Signal

B153A 00

B153A 00

B153A 00

B153A 08

Position Sensor Signal 1

B153E 02

B153E 05, B153E 08

B153E 05

--

Position Sensor Signal 2

B153E 02

B153E 05, B153E 08

B153E 05

--

Ratchet Switch Signal

B153A 00

B153A 00

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

--

Liftgate Motor Open Control

B396A 02

B396A 04

B396A 01

--

Full Open Low Reference

--

2

2

--

Liftgate Switches Low Reference

--

1

1

--

Position Sensor Low Reference

--

B0153E 08

2

--

I/P Switch Ground

--

1

1

--

Liftgate Control Module Ground

--

2

2

--

1. Liftgate Switch Malfunction

2. Liftgate Malfunction

Circuit/System Description

The liftgate control module (LGM) continuously monitors power liftgate operation and calculates its location and direction of travel using 2 Hall effect sensors that are part of the gear motor assembly. The Hall effect sensors are 5-volt 3-wire sensors and are supplied with a 5-volt power, ground and signal circuits from the LGM. The Hall effect sensor signal circuits are referenced from voltage within the LGM and pulsed low by the Hall effect sensors.

Conditions for Running the DTC

The system voltage is 9-16 volts.

Conditions for Setting the DTC

B153E 02

The LGM detects a short to ground in the liftgate motor assembly position sensor circuit.

B153E 05

The LGM detects a short to voltage or an open/high resistance in the liftgate motor assembly position sensor circuit.

B153E 08

The LGM does not detect optical sensor pulses when the liftgate is in motion.

Action Taken When the DTC Sets

The power liftgate system will be disabled.

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 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

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

  1. Ignition ON, doors unlocked, transaxle in Park, enable the power liftgate by pressing the liftgate enable/disable button on the I/P switch assembly.
  2. Open the liftgate by pressing the touchpad on the liftgate handle switch. The liftgate should release and power open.
  3. Close the liftgate by pressing the liftgate button switch. The liftgate should power close, cinch-in, and latch.

Circuit/System Testing

  1. Ignition OFF, disconnect the X3 harness connector at the LGM.
  2. Ignition OFF, test for less than 1 ohm between the low reference terminal 11 at the LGM and ground.
  3. If not the specified range, replace the LGM.
  4. Ignition ON, test for 4.8-5.2 volts between 5-volt reference terminal 8 at the LGM and ground.
  5. If greater than the specified value, replace the LGM.
  6. Ignition ON, test for 4.8-5.2 volts are between sensor 1 signal terminal 9 and low reference terminal 11 at the LGM.
  7. If not within the specified range, replace the LGM.
  8. Test for 4.8-5.2 volts between sensor 2 signal terminal 10 and low reference terminal 11 at the LGM.
  9. If not within the specified range, replace the LGM.
  10. If all circuits test normal, test or replace the liftgate motor assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Liftgate Close Actuator Motor Replacement
    •  Control Module References for LGM replacement, setup and programming