Liftgate Release Malfunction (Manual)
Liftgate Release Malfunction (Manual)
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 voltage 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 relay. When the liftgate switch signal is activated, the BCM enables the liftgate release relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the liftgate release relay control circuit. 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 Procedures for the appropriate procedure.
If the vehicle has a history of the liftgate opening unexpectedly, inspect the point where the wires enter the liftgate unlatch switch for corrosion or evidence of water intrusion.
Reference Information
Schematic Reference
Release Systems Schematics Release Systems Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Rear Hatch/Gate Description and Operation Rear Hatch/Gate
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Command the liftgate to UNLATCH with a scan tool. The liftgate latch assembly should release the liftgate.
• If the liftgate latch assembly does not release the liftgate, refer to Liftgate Latch Malfunction (Except UA2/UTC).
• If the liftgate latch assembly does not release the liftgate, refer to Liftgate Latch Malfunction (With UA2/UTC).
2. With the doors unlocked, command the liftgate latch to release by pressing the liftgate unlatch switch. The liftgate latch should release the liftgate.
• If the value does not change, refer to Liftgate Release Switch Malfunction.
Circuit/System Testing
Liftgate Latch Malfunction (Except UA2/UTC)
1. Ignition OFF, disconnect the harness connector at the A23C liftgate latch assembly.
2. Test for less than 5 ohm between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect the harness connector at the A23C liftgate latch assembly.
4. Disconnect the X3 harness connector at the X53A fuse block-rear body.
5. Briefly connect a 15 A fused jumper wire between the control circuit terminal 8 and B+. Verify the A23C liftgate latch assembly activates.
• If the A23C liftgate latch assembly does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the A23C liftgate latch assembly.
6. Connect a test lamp between the control circuit terminal 21 and ground.
7. Command the liftgate to UNLATCH with a scan tool. The test lamp should illuminate during the unlatch command.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• 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 K9 BCM.
8. Connect a test lamp between the control circuit terminal 12 and B+.
9. Command the liftgate to UNLATCH with a scan tool. The test lamp should illuminate during the unlatch command.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
10. If all circuits test normal, replace the X53A fuse block-rear body.
Liftgate Latch Malfunction (With UA2/UTC)
1. Ignition OFF, disconnect the X2 harness connector at the X53A fuse block-rear body.
2. Test for less than 5 ohm between the ground circuit terminal 27 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect the X2 harness connector and disconnect the X3 harness connector at the X53A fuse block-rear body.
4. Connect a test lamp between the control circuit terminal 21 and ground.
5. Command the liftgate to UNLATCH with a scan tool. The test lamp should illuminate during the unlatch command.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• 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 K9 BCM.
6. Connect a test lamp between the control circuit terminal 12 and B+.
7. Command the liftgate to UNLATCH with a scan tool. The test lamp should illuminate during the unlatch command.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
8. Connect the X3 harness connector at the X53A fuse block-rear body and disconnect the harness connector at the A23C liftgate latch assembly.
9. Connect a test lamp between the control circuit terminal 1 and ground.
10. Command the liftgate to UNLATCH with a scan tool. The test lamp should illuminate during the unlatch command.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the X53A fuse block-rear body.
• 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 X53A fuse block-rear body.
11. Connect a test lamp between the control circuit terminal 3 and B+.
12. Command the liftgate to UNLATCH with a scan tool. The test lamp illuminate during the unlatch command.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the X53A fuse block-rear body.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the X53A fuse block-rear body.
13. If all circuits test normal, test or replace the A23C liftgate latch assembly.
Liftgate Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S45B liftgate unlatch switch.
2. Test for less than 10 ohm between the ground circuit terminal 1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for greater than 10V between the signal circuit terminal 2 and the ground circuit terminal 1.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
4. If all circuits test normal, test or replace the S45B liftgate unlatch switch.
Component Testing
Liftgate Latch Assembly
1. Ignition OFF, disconnect the X1 harness connector at the A23C liftgate latch assembly.
2. Install a 15 A fused jumper wire between the control terminal 1 and 12 V. Momentarily install a jumper wire between the ground terminal 3 and ground. Verify the A23C liftgate latch assembly activates.
• If the actuator does not perform as specified, replace the A23C liftgate latch assembly.
Liftgate Release Switch
1. Ignition OFF, disconnect the harness connector at the S46B liftgate unlatch switch.
2. Test for infinite resistance between the signal terminal 2 and the ground terminal 1 with the switch in the open position.
• If not the specified value, replace the S46B liftgate unlatch switch.
3. Test for less than 2 ohm between the signal terminal 2 and the ground terminal 1 with the switch in the closed position.
• If greater than the specified range, replace the S46B liftgate unlatch switch.
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 Control Module References for BCM replacement, setup and programming