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 B396F 05: Liftglass Ajar Output Circuit Short to Battery or Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Liftgate Position Sensor 5 V Reference Voltage

B153E 08

2

2

--

Liftgate Disable Signal

1, 2

1

1

--

Liftgate Open Signal - Exterior Switch

B396E 02

1

1

--

Liftgate Open Signal - Shut Face Switch

B396E 02

1

1

--

Object Sensors Signal

B153F 02

B153F 05

B153F 05

B153F 03, B153F 07

Liftgate Open Signal - Exterior Switch

B396E 02

1

1

--

Open/Close Switches Signal

B396D 02

1, 2

1, 2

--

Pawl Switch Signal

B153A 08

B153A 08

B153A 08

B153A 08

Position Sensor Signal 1

B153E 08

B153E 08

B153E 08

B153E 08

Position Sensor Signal 2

B153E 08

B153E 08

B153E 08

B153E 08

Ratchet Switch Signal

B153A 08

B153A 08

B153A 08

B153A 08

Sector Switch Signal

B153A 08

B153A 08

B153A 08

B153A 08

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

--

Liftgate Switches Low Reference

--

B153A 08

1

B153E 08

Position Sensor Low Reference

--

B0153E 08

2

--

Mode/Release Switch Ground

--

1

1

--

Liftgate Control Module Ground

--

U0230 00

2

--

1. Liftgate Switch Malfunction

2. Liftgate Malfunction

Circuit/System Description

The liftgate control module supplies power and ground to the liftgate clutch, which is part of the liftgate motor assembly. Upon receiving a liftgate open request, the liftgate control module supplies voltage to the clutch via the liftgate motor engage control circuit. The liftgate motor disengage control circuit supplies a ground. With the clutch energized, the motor output is mechanically connected to the liftgate and power liftgate operation is allowed. The liftgate motor clutch engages or disengages the liftgate motor to the liftgate drive gear and is the component that determines power or manual operation.

Conditions for Running the DTC

The system voltage is 9.5-16 V.

Conditions for Setting the DTC

B396F 05

The liftgate control module detects a short to voltage or open in the liftgate ajar switch signal circuit.

Action Taken When the DTC Sets

When an open or short to voltage condition exists, the rear wiper motor will not operate.

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

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

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

Reference Information

Schematic Reference

Liftgate Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Rear Hatch/Gate 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 ajar switch parameter while opening and closing the liftgate. The reading should toggle between Active and Inactive.

Circuit/System Testing

  1. Ignition OFF, disconnect the X3 harness connector at the K39 Liftgate Control Module.
  2. Test for less than 5 Ω between the low reference terminal 2 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K39 Liftgate Control Module.
  4. Ignition ON, verify with a scan tool the liftgate ajar switch parameter is Inactive.
  5. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuits test normal, replace the K39 Liftgate Control Module.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool liftgate ajar switch parameter is Active.
  7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the K39 Liftgate Control Module.
  8. If all circuits test normal, replace the A23C Door Latch Assembly - Liftgate.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Liftgate Latch Replacement
    •  Control Module References for liftgate control module replacement, setup, and programming