Liftgate Release Malfunction (Manual Liftgate)
Liftgate Release Malfunction (Manual Liftgate)
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 exterior liftgate control switch is an input to the body control module (BCM). The BCM supplies a signal to the exterior liftgate control switch and when the switch is pressed, signal circuit voltage goes low. When the BCM receives a liftgate release signal, the BCM will supply voltage and ground to the L/GATE relay coil, energizing the relay. When the relay is energized, battery voltage flows through the closed contacts of the relay to the liftgate latch assembly which activates allowing for the liftgate to be raised to the open position.
Diagnostic Aids
Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power () 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 ()
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
1. Ignition ON, observe the scan tool Liftgate Handle Sw. parameter while pressing and releasing the liftgate release switch. The parameter should change between Active and Inactive.
• If the parameter does not change, refer to Liftgate Release Switch Malfunction.
2. Command the liftgate to UNLATCH by pressing the exterior liftgate control switch. The liftgate latch assembly should UNLATCH and release the liftgate.
• If the liftgate latch assembly does not UNLATCH, refer to Liftgate Latch Malfunction.
Circuit/System Testing
Liftgate Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the exterior liftgate control switch.
2. Test for less than 1.0 ohm between the ground circuit terminal 2 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 Sw. parameter is Inactive.
• If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Liftgate Handle Sw. parameter is Active.
• If not the specified parameter, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the exterior liftgate control switch.
Liftgate Latch Malfunction
1. Ignition OFF, disconnect the L/GATE relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 87 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 30 for a short to ground. If the circuit tests normal, test or replace the L/GATE relay.
4. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
5. Test for less than 1.0 ohm between the ground circuit terminal 3 and ground
• If greater than the specified range, test the ground circuit for an open/high resistance.
6. Connect the harness connector at the liftgate latch assembly.
7. Ignition ON, connect a 15A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the liftgate latch assembly is activated.
• If the liftgate latch assembly does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the liftgate latch assembly.
8. Connect a test lamp between the control circuit terminal 85 and ground.
9. Command the liftgate latch to release by pressing and releasing the exterior liftgate control switch. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the 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 BCM.
10. Connect a test lamp between the control circuit terminal 86 and B+.
11. Command the liftgate latch to release by pressing and releasing the exterior liftgate control switch. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• 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 BCM.
12. If all circuits test normal, test or replace the L/GATE relay.
Component Testing
Liftgate Latch Assembly
1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
2. Install a 15A fused jumper wire between the control terminal 1 and 12V. Install a jumper wire between the ground terminal 3 and ground. Verify the release actuator activates.
• If the actuator does not perform as specified, replace the liftgate latch assembly.
Exterior Liftgate Control Switch
1. Ignition OFF, disconnect the harness connector at the exterior liftgate control switch.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 2 with the switch in the open position.
• If not the specified value, replace the exterior liftgate control switch.
3. Test for less than 2.0 ohms between the signal terminal 1 and the ground terminal 2 with the switch in the closed position.
• If greater than the specified range, replace the exterior liftgate control switch.
Relay Test
1. Ignition OFF, disconnect the L/GATE relay.
2. Test for 60-200 ohms between terminals 85 and 86.
• If not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If not the specified value, replace the L/GATE relay.
4. Install a 3A fused jumper wire between relay terminal 85 and 12V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
• If greater than the specified range, replace the L/GATE relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Liftgate Latch Replacement ()
* Liftgate Outside Handle Replacement ()
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming