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Trunk Release Inoperative



Trunk Release Inoperative

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

When the ignition is ON, the body control module (BCM) supplies battery positive voltage to the rear compartment lid release switch through the trunk release switch supply voltage circuit. When the rear compartment lid release switch is operated, the trunk release supply voltage circuit is grounded through the switch ground circuit and the voltage is pulled low within the BCM. In response, the BCM applies battery positive voltage to the trunk release relay control circuit, which energizes the coil side of the trunk relay. The switch side of the trunk relay then closes, supplying battery positive voltage through the relay and the latch motor voltage control circuit to the rear compartment lid latch. The rear compartment lid latch, which is grounded to G402, then releases the rear compartment lid so that it may be manually raised to an open position.


Diagnostic Aids

The RR TRN/SIG fuse also provides battery positive voltage to the BCM which provides power to many systems including the trunk release relay control which, if open, will cause the rear compartment lid latch to become inoperative.


Reference Information
Schematic Reference

* Release Systems Schematics (Release Systems Schematics)
* Theft Deterrent System Schematics (Theft Deterrent System Schematics)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Luggage Compartment Description and Operation (Description and Operation)
Electrical Information Reference

* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Circuit Testing (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Programming and Relearning (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, observe the scan tool Valet Switch parameter while pressing the top and bottom of the valet switch. The parameter should change between Active and Inactive.

• If the Valet Switch parameters do not change, refer to Valet Switch Malfunction.

2. Observe the scan tool Int Trunk Sw parameter while pressing and releasing the rear compartment lid release switch button. The parameter should change between Active and Inactive.

• If the Trunk Rel Sw parameters do not change, refer to Trunk Release Switch Malfunction.

3. Command the trunk release with a scan tool, the rear compartment lid latch should release the trunk lid.

• If the rear compartment lid latch does not release, refer to Rear Compartment Lid Latch Malfunction.




Circuit/System Testing


Valet Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the valet switch.
2. Test for less than 1.0 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. Ignition ON, verify the scan tool Valet Switch parameter is Inactive.

• If not the specified parameter, 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 Valet Switch 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 valet switch.



Trunk Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 1.0 ohm between the ground circuit terminal 8 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Int Trunk Sw parameter is Inactive.

• If not the specified parameter, test the signal circuit terminal 10 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 10 and ground. Verify the scan tool Int Trunk Sw 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 headlamp switch.



Rear Compartment Lid Latch Malfunction
1. Ignition OFF, disconnect the TRK REL relay.
2. Test for less than 1.0 ohm between the relay coil ground circuit terminal and ground.

• If greater than the specified range, test 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 output circuit for a short to voltage.

4. Verify that a test lamp illuminates between the relay coil 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.

5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
6. Test for less than 1.0 ohm between the rear compartment lid latch ground circuit terminal 3 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the rear compartment lid latch.
8. Ignition ON, connect a 10-A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal. Verify the rear compartment lid latch is activated.

• If the rear compartment lid latch does not activate, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.

9. Connect a test lamp between the relay coil control circuit terminal and ground.
10. Command the trunk 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.

11. If all circuits test normal, test or replace the TRK REL relay.



Component Testing


Relay Test
1. Ignition OFF, disconnect the TRK REL relay.
2. Test for 60-180 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 relay.

4. Install a 25A 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 between terminals 30 and 87.

• If greater than the specified range, replace the relay.




Rear Compartment Lid Latch
1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Install a 10-amp fused jumper wire between the control terminal 4 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the rear compartment lid latch activates.

• If the latch does not perform as specified, replace the rear compartment lid latch.




Headlamp Switch
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for infinite resistance between the signal terminal 10 and the ground terminal 8 with the switch in the open position.

• If not the specified value, replace the headlamp switch.

3. Test for less than 2.0 ohms between the signal terminal 10 and the ground terminal 8 with the switch in the closed position.

• If greater than the specified range, replace the headlamp switch.




Valet Switch
1. Ignition OFF, disconnect the harness connector at the valet 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 valet switch.

3. Test for less than 2.0 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 valet switch.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Rear Compartment Lid Latch Replacement (Service and Repair)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Headlamp Switch Replacement (Service and Repair)
* Programming and Relearning (Programming and Relearning) for BCM replacement, setup and programming


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