Liftgate Release Malfunction (With TB4)
Liftgate Release Malfunction (With TB4)
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.
Diagnostic Fault Information
Circuit/System Description
The liftgate switch is an input to the Body Control Module (BCM). The BCM supplies 12 volts to the signal circuit and when the liftgate switch is activated the signal circuit voltage goes low. The BCM controls the Liftgate Latch Assembly through the liftgate release printed circuit board relay. When the liftgate switch signal is activated, the BCM enables the liftgate release relay by applying battery voltage to the relay circuit high and the relay is energized when the BCM grounds the relay control circuit low. When the relay is energized battery voltage is supplied to the Liftgate Latch Assembly through the liftgate latch control circuit.
Diagnostic Aids
Before testing can be performed, the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power Service and Repair for the appropriate procedure.
Reference Information
Schematic Reference
Release Systems Schematics Release Systems Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left Front
Description and Operation
Rear Hatch/Gate Description and Operation Rear Hatch/Gate
Electrical Information Reference
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Circuit Testing Circuit Testing
* Wiring Repairs Wiring Repairs
* Connector Repairs Connector Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the operation of the liftgate when commanding the Liftgate Window Unlatch with a scan tool.
• If the If the A23C Liftgate Latch Assembly does not UNLATCH
Refer to Circuit/System Testing - Liftgate Latch Inoperative.
• If the If the A23C Liftgate Latch Assembly does UNLATCH
3. Verify the operation of the liftgate when commanding the A23C Liftgate Latch Assembly to UNLATCH by pressing the S46 Liftgate Handle Switch.
• If the A23C Liftgate Latch Assembly does not UNLATCH
Refer to Circuit/System Testing - Liftgate Release Switch Inoperative
• If the A23C Liftgate Latch Assembly does UNLATCH
4. All OK.
Circuit/System Testing
Liftgate Latch Inoperative
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A23C Liftgate Latch Assembly. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 3 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Connect the harness connector at the A23C Liftgate Latch Assembly and disconnect the X2 harness connector at the X50A Fuse Block-Underhood
4. Ignition ON, connect a 15 A fused jumper wire between the control circuit terminal A8 and B+.
5. Verify the A23C Liftgate Latch Assembly is activated.
• If the A23C Liftgate Latch Assembly does not activate
1. Ignition OFF, disconnect the harness connector at the A23C Liftgate Latch Assembly.
2. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms
3. Test for infinite resistance between the control circuit terminal A8 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the A23C Liftgate Latch Assembly
• If the A23C Liftgate Latch Assembly activates
6. Ignition OFF, connect the harness connector at the A23C Liftgate Latch Assembly and disconnect the X4 and the X5 harness connectors at the K9 Body Control Module.
7. Ignition ON, connect a 3 A fused jumper wire between the control circuit terminal 8 X4 and B+.
8. Connect a jumper wire between the control circuit terminal 20 X5 and ground.
9. Verify the A23C Liftgate Latch Assembly activates.
• If the A23C Liftgate Latch Assembly does not activate
1. Ignition OFF.
2. Test for infinite resistance between either control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in each control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the X50A Fuse Block-Underhood.
• If the A23C Liftgate Latch Assembly activates
10. Replace the K9 Body Control Module.
Liftgate Release Switch Inoperative
1. Ignition OFF, disconnect the harness connector at the S46 Liftgate Handle Switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Test for greater than 10 V between the signal circuit terminal 1 and ground.
• If 10 V or less
1. Ignition OFF, disconnect the X6 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance on the circuit.
• If less than 2 ohms, replace the K9 Body Control Module.
• If greater than 10 V
5. Connect a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
6. Verify the A23C Liftgate Latch Assembly is activated.
• If the A23C Liftgate Latch Assembly does not activate
1. Ignition OFF, disconnect the X6 harness connector at the K9 Body Control Module. Ignition ON
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If the A23C Liftgate Latch Assembly activates
7. Test or replace the S46 Liftgate Handle Switch.
Component Testing
Liftgate Release Switch
1. Ignition OFF, disconnect the harness connector at the S46 Liftgate Handle Switch.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 2 with the switch in the open position.
• If less than infinite resistance
Replace the S46 Liftgate Handle Switch.
• If infinite resistance
3. Test for less than 3 ohms between the signal terminal 1 and the ground terminal 2 with the switch in the closed position.
• If 3 ohms or greater
Replace the S46 Liftgate Handle Switch.
• If less than 3 ohms
4. All OK
Liftgate Latch
1. Ignition OFF, disconnect the harness connector at the A23C Liftgate Latch Assembly.
2. Install a 15 A fused jumper wire between the control terminal 1 and 12 V. Install a jumper wire between the ground terminal 3 and ground.
3. Verify the A23C Liftgate Latch Assembly activates
• If the A23C Liftgate Latch Assembly does not activate.
Replace the A23C Liftgate Latch Assembly.
• If the A23C Liftgate Latch Assembly does activate.
4. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Liftgate Release Switch Replacement Liftgate Release Switch Replacement
* Liftgate Latch Replacement Service and Repair
* Accessory Wiring Junction Block Replacement Accessory Wiring Junction Block Replacement
* Control Module References Programming and Relearning for BCM replacement, setup and programming