Liftgate Release Malfunction
Liftgate Release Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) 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 battery 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 RLYS relay. When the liftgate switch signal is activated, the BCM enables the RLYS relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the RLYS 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.
Reference Information
Schematic Reference
Release Systems Schematics (Release Systems Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Rear Hatch/Gate Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Unlock all doors using the driver door lock switch. Command the liftgate release by pressing the liftgate release switch. The liftgate latch assembly should release the liftgate.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
2. Test for less than 1 ohm between the ground circuit terminal A and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for infinite resistance between the signal terminal B and the ground terminal A with the switch in the open position.
• If not the specified value, replace the liftgate release switch.
4. Test for less than 2 ohms between the signal terminal B and the ground terminal A with the switch in the closed position.
• If greater than the specified range, replace the liftgate release switch.
5. Test for greater than 10 volts between the signal circuit terminal B and ground.
• If less than the specified range, test the signal circuit for a short to ground or and open/high resistance. If the circuit tests normal, replace the BCM.
6. Ignition OFF, connect the harness connector at the liftgate release switch and disconnect the harness connector at the liftgate latch assembly.
7. Test for less than 1 ohm between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
8. Connect the harness connector at the liftgate latch and disconnect the X1 harness connector at the I/P fuse block.
9. Verify that a test lamp does not illuminate between the control circuit terminal 23 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
10. Connect a 10A fused jumper wire between the control circuit terminal 23 and B+. Verify that the liftgate latch activates.
• If the liftgate latch 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 liftgate latch assembly.
11. Ignition OFF, connect the X1 harness connector at the I/P fuse block and disconnect the X4 and X7 harness connectors at the BCM.
12. Connect a 10A fused jumper wire between the control circuit terminal 13 and B+. Verify the liftgate latch does not activate
• If the liftgate latch activates, test the control circuit terminal 22 for a short to ground. If the circuit tests normal replace the I/P fuse block.
• If the jumper wire fuse opens, test the control circuit terminal 13 for a short to ground. If the circuit tests normal replace the I/P fuse block.
13. Briefly connect another jumper wire between the control circuit terminal 22 and ground. Verify the liftgate latch activates.
• If the liftgate latch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal replace the I/P fuse block.
14. If all circuits test normal, replace the BCM.
Component Testing
Liftgate Latch Assembly
1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
2. Install a 10A fused jumper wire between the control terminal 1 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the liftgate latch actuator activates.
• If the actuator does not perform as specified, replace the liftgate latch assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Liftgate Outside Handle Replacement (Service and Repair)
* Instrument Panel Wiring Harness Junction Block Replacement (Service and Repair)
* Liftgate Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming