Liftgate Release Malfunction
Liftgate Release Malfunction
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 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 Service and Repair for the appropriate procedure.
An intermittent short to ground in the Liftgate Unlatch Switch Signal circuit may cause the BCM to command the liftgate to open if the vehicle is in park and the doors are unlocked. If the vehicle has a history of the liftgate opening unexpectedly, inspect the point where the wires enter the exterior liftgate handle 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 1-2 Shift Solenoid (SS) Valve (MN5)
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 Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Liftgate Handle Switch parameter while pressing and releasing the S46B liftgate release switch. The parameter should change between Active and Inactive as the switch is pressed and released.
• If the value does not change, refer to Liftgate Release Switch Malfunction
2. Command the Rear Body Closure to Unlatch with a scan tool. The A23 liftgate latch assembly should release the liftgate.
• If the A23 liftgate latch assembly does not release the liftgate, refer to Liftgate Release Malfunction.
Circuit/System Testing
Liftgate Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S46B liftgate release switch.
2. Test for less than 1 ohms between the ground circuit terminal A and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Liftgate Handle Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Liftgate Handle Switch parameter is Active.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, test or replace the S46B liftgate release switch.
Liftgate Release Malfunction
1. Ignition OFF, disconnect the harness connector at the liftgate latch.
2. Test for less than 5 ohms 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 a test lamp between the control circuit terminal 1 and ground.
4. Ignition ON, command the liftgate latch to UNLATCH by pressing the liftgate release switch. 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 fuse block-instrument panel.
• If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the liftgate latch.
• If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, refer to Instrument Panel Fuse Block Test.
5. If all circuits test normal, test or replace the liftgate latch.
Instrument Panel Fuse Block Test
1. Ignition OFF, disconnect the X4 and X7 harness connectors at the body control module.
2. Connect a 10 A fused jumper wire between the control circuit terminal 13 X7 and B+, briefly connect a jumper wire between the control circuit terminal 22 X4 and ground. Verify the liftgate latch is activated.
• If the liftgate latch does not activate, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the fuse block-instrument panel.
3. If all circuits test normal, replace the body control module.
Component Testing
Liftgate Latch Assembly
1. Ignition OFF, disconnect the harness connector at the A23C liftgate latch assembly.
2. Install a 10 A fused jumper wire between the control terminal 1 and 12 V. Install a jumper wire between the ground terminal 3 and ground. Verify the A23C liftgate latch assembly activates.
• If the A23C liftgate latch assembly 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 release switch.
2. 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 S46B liftgate release switch.
3. 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 S46B liftgate release switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Liftgate Outside Handle Replacement Service and Repair
* Instrument Panel Wiring Harness Junction Block Replacement Instrument Panel Wiring Harness Junction Block Replacement
* Liftgate Latch Replacement Service and Repair
* Control Module References Programming and Relearning for BCM replacement, programming and setup