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Liftgate Release Inoperative (Manual Liftgate)



LIFTGATE RELEASE INOPERATIVE (MANUAL LIFTGATE)

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 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 L/GATE relay. When the liftgate switch signal is activated, the BCM enables the L/GATE relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the L/GATE relay control circuit. When the relay is energized battery voltage is supplied to the liftgate latch assembly through the liftgate latch control circuit.

CIRCUIT/SYSTEM VERIFICATION
1. Ignition ON, observe the Liftgate Release Sw parameter while pressing the Liftgate Release Switch. The reading should change between Active and Inactive.
- If the reading does not change between Active and Inactive, refer to Liftgate Switch Malfunction.
2. Ignition ON, observe the Liftgate Release Cmd parameter while pressing the Liftgate Release Switch. The reading should change between On and Off.
- If the reading does not change between On and Off, refer to Liftgate Latch Malfunction.

CIRCUIT/SYSTEM TESTING

Liftgate Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the Liftgate switch.
2. Ignition OFF, test for less than 1.0 ohm for resistance 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 Release 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 Release 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 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 40 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 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 PDM fuse is open, test the control circuit terminal 40 for a short to ground.
4. Ignition OFF, disconnect the harness connector at the Liftgate Latch Assembly
5. Ignition OFF, test for less than 1.0 ohm of resistance between the Liftgate Latch Assembly ground circuit terminal 3 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
6. Ignition OFF, connect the harness connector at the Liftgate Latch Assembly.
7. Ignition ON, connect a 15A fused jumper wire between the B+ circuit terminal and the control circuit terminal 40. 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.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
8. Connect a test lamp between the relay coil control circuit terminal 22 circuit and ground.
9. Command the Liftgate Release ON and OFF with a scan tool. 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 B+ circuit and the relay coil low reference circuit terminal 69.
11. Command the Liftgate Release ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the low reference circuit for a short to ground. If the circuit tests normal, replace the BCM.
- If the test lamp is always OFF, test the low reference circuit for 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.
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 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 relay
2. Test for 60-200 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 less than infinite resistance, replace the L/GATE relay
4. Install a 3-amp fused jumper wire between applicable relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Measure for less than 2 ohms of resistance between terminals 30 and 87.
- If greater than 2 ohms, replace the L/GATE relay

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for BCM replacement, setup, and programming. Programming and Relearning
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