Trunk Release Inoperative
Trunk Release Inoperative
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
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 ground 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 G302, then releases the rear compartment lid so that it may be manually raised to an open position.
Circuit/System Verification
1. Ignition ON, observe the scan tool Trunk Release Switch parameter while pressing and releasing the rear compartment lid release switch button. The parameter should change between Active and Inactive.
^ If the parameter does not change, refer to Trunk Release Switch Malfunction.
2. 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
Trunk Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the rear compartment lid release switch.
2. Test for less than 15 ohms between 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 Trunk Release Switch parameter is Inactive.
^ If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3-amp fused jumper wire between the signal circuit terminal C and the ground circuit terminal A. Verify the scan tool Trunk Release 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 rear compartment lid release switch.
Rear Compartment Lid Latch Malfunction
1. Ignition OFF, disconnect the TRUNK relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 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 85 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 B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the TRUNK relay.
4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground.
^ If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
6. 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.
7. Connect the harness connector at the rear compartment lid latch.
8. Ignition ON, connect a 10A fused jumper wire between the relay switch B+ circuit terminal 30 and the control circuit terminal 87. Verify the rear compartment lid latch is activated.
^ If the rear compartment lid latch does not activate, test the control 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 B+ circuit terminal 85 and the control circuit terminal 86.
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 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.
11. If all circuits test normal, test or replace the TRUNK relay.
Component Testing
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.
Rear Compartment Lid Release Switch
1. Ignition OFF, disconnect the harness connector at the rear compartment lid release switch.
2. Test for infinite resistance between the trunk release switch signal terminal C and the ground terminal A with the switch in the open position.
^ If less than the specified value, replace the rear compartment lid release switch.
3. Test for less than 2 ohms of between the trunk release switch signal terminal C and the ground terminal A with the switch in the closed position.
^ If greater than the specified range, replace the rear compartment lid release switch.
4. Test for infinite resistance between each terminal and the lid release switch housing/case.
^ If less than the specified value, replace the rear compartment lid release switch.
Relay Test
1. Ignition OFF, disconnect the TRUNK relay.
2. Test for 65-90 ohms between terminals 85 and 86.
^ If not 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 10-amp fused jumper wire between the 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.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Rear Compartment Lid Latch Replacement
* Rear Compartment Lid Switch Replacement
* Relay Replacement (Attached to Wire Harness)