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Liftgate Release Inoperative (Panel Van)



LIFTGATE RELEASE INOPERATIVE (PANEL VAN)

DIAGNOSTIC INSTRUCTIONS
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.




DIAGNOSTIC FAULT INFORMATION

CIRCUIT/SYSTEM DESCRIPTION
The liftgate can be released by pressing the liftgate touchpad located in the handle above the license plate. All doors must be unlocked, the transaxle must be in park or a vehicle with a manual transaxle, the vehicle must be stationary for the liftgate to release.

The access panel release system consists of a primary relay, three secondary relays, three diodes, three release switches and three latches. When the appropriate release switch is pressed, the liftgate release signal circuit to the body control module (BCM) is grounded, the BCM detects a drop in voltage and the BCM enables the access panel release system by supplying voltage to the L/GATE RELSE relay coil. With the relay energized, battery positive voltage is allowed from the relay switched input through the switch contacts and out the relay switched output to the access panel release system and to the appropriate access panel/liftgate relay and latch. The release switch, when pressed, simultaneously provides a ground for the appropriate coil side access panel/liftgate relay, a diode prevents feedback in the liftgate release switch signal circuit.

The liftgate release system is different from the side access panel release system, when the relay is energized, battery positive voltage is allowed from the relay switched input through the switch contacts and out the relay switched output to the liftgate door latch release actuator and releasing the liftgate. Ground for the liftgate door latch release actuator is provided by G402.

CIRCUIT/SYSTEM VERIFICATION
1. Ignition ON, observe the operation of the rear access panels while pressing the Rear Access Panel switches. The access panels should release.
- If one or more access panels do not release, refer to Access Panel Release Inoperative. Access Panel Release Inoperative
2. Ignition ON, observe the scan tool Liftgate Release Sw parameter while pressing and releasing the liftgate release switch. The reading should change between Active and Inactive
- If the reading does not change between specified values, refer to Liftgate Release Switch Malfunction.
3. Observe the operation of the liftgate while pressing the Liftgate Release Switch. The liftgate should release.
- If the liftgate does not release, refer to Liftgate Release Malfunction.

CIRCUIT/SYSTEM TESTING

Liftgate Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the Liftgate Release Switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal D 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 Release Sw 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 BCM.
4. Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Liftgate Release 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 BCM.
5. If all circuits test normal, test or replace the Liftgate Release Switch.

Liftgate Release Malfunction
1. Ignition OFF, disconnect the L/GATE RELSE relay.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the relay coil ground circuit terminal and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal and ground.
- If the test lamp illuminates, test the control circuit for a short to voltage.
4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the L/GATE/S ROOF fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test for a malfunction in the following components.
- Liftgate Relay
- Rear Access Panel Relay-LR
- Rear Access Panel Relay-RR
- Rear Access Panel Latch-LR
- Rear Access Panel Latch-RR

5. Connect a test lamp between the Liftgate Release Relay Control terminal and the relay coil ground circuit terminal.
6. Command the Liftgate Release ON and OFF by pressing the Liftgate Release 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.
7. Connect the L/GATE RELSE relay.
8. Disconnect the Liftgate relay.
9. Verify that a test lamp does not illuminate between the relay coil B+ circuit and ground.
- If the test lamp illuminates, test the B+ circuit for a short to voltage. If the circuit tests normal, test or replace the L/GATE RELSE relay.
10. Ignition OFF, test for less than 5.0 ohms of resistance between the relay coil ground circuit terminal and ground while pressing the Liftgate Release Switch.
- If greater than the specified range, test the ground circuit for an open/high resistance.
11. Ignition ON, verify a test lamp illuminates between the relay coil B+ circuit terminal and ground while pressing the Liftgate Release Switch.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the L/GATE RELSE relay.
12. Verify a test lamp illuminates between the relay switch B+ circuit terminal and ground while pressing the Liftgate Release Switch.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
13. Connect the Liftgate relay.
14. Disconnect the harness connector at the Liftgate Door Latch.
15. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal 3 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
16. Ignition ON, connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 3.
17. Press and release the Liftgate Release 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, test or replace the Liftgate relay.
- 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, test or replace the Liftgate relay.
18. If all circuit test normal, test or replace the Liftgate Door Latch.

COMPONENT TESTING

Release Actuator, Liftgate Door Latch
1. Ignition OFF, disconnect the harness connector at the Liftgate Door Latch.
2. Install a 20-amp fused jumper wire between the control circuit terminal 1 and 12 volts. Install a jumper wire between the ground circuit terminal 3 and ground. Verify the release actuator activates.
- If the actuator does not perform as specified, replace the Liftgate Door Latch.

Liftgate Release Switch
1. Ignition OFF, disconnect the harness connector at the Liftgate Release switch.
2. Test for infinite resistance between the signal terminal B and the ground circuit terminal D with the switch in the open position.
- If not the specified value, replace the Liftgate Release switch.
3. Test for less than 2.0 ohms between the signal terminal B and the ground circuit terminal D with the switch in the closed position.
- If greater than the specified range, replace the Liftgate Release switch.

Relay Test
1. Ignition OFF, disconnect the L/GATE RELSE relay.
2. Test for 60-180 ohms of resistance between terminals 85 and 86.
- If the resistance is 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 relay.

4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms of resistance between terminals 30 and 87.
- If greater than the specified range, replace the relay.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
- Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)
- Liftgate Outside Handle Replacement
- Control Module References for BCM replacement, setup and programming. Programming and Relearning
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