Trunk Release Malfunction
Trunk Release Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies a 12 V reference voltage to the rear compartment lid unlatch switch through the release switch signal circuit. When the rear compartment lid unlatch switch is pressed, the release switch signal circuit is grounded through the rear compartment lid unlatch switch ground circuit and the reference voltage is pulled low within the BCM. In response, the BCM applies battery positive voltage to the compartment lid release relay control circuit, which energizes the coil side of the relay. The switch side of the compartment lid release relay then closes, supplying battery positive voltage through the relay and the rear compartment lid latch control circuit activating the latch so that the trunk lid may be manually raised to an open position.
Reference Information
Schematic Reference
Release Systems Schematics Release Systems Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Luggage Compartment Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Interior Trunk Lid/Liftgate Window Unlatch Switch parameter while pressing and releasing the S58A rear compartment lid unlatch switch-exterior. The parameter should be Inactive and change to Active when the switch is pressed.
• If the value does not change between Active and Inactive, refer to Rear Compartment Lid Switch Malfunction.
2. Command the M40 rear compartment lid latch to UNLATCH with a scan tool. The M40 rear compartment lid latch should release the deck lid.
• If the M40 rear compartment lid latch does not does not release, refer to Rear Compartment Lid Malfunction.
Circuit/System Testing
Rear Compartment Lid Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S58A rear compartment lid unlatch switch-exterior.
2. Test for less than 10 ohms between the ground circuit terminal 3 and ground
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify the scan tool Interior Trunk Lid/Liftgate Window Unlatch Switch 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 K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Interior Trunk Lid/Liftgate Window Unlatch Switch 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 K9 BCM.
5. If all circuits test normal, test or replace the S58A rear compartment lid unlatch switch-exterior.
Rear Compartment Lid Malfunction
1. Ignition OFF, disconnect the harness connector at the M40 rear compartment lid latch.
2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for and open/high resistance.
3. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2.
4. Ignition ON, command the M40 rear compartment lid latch to UNLATCH with a scan tool. The test lamp should briefly illuminate during the UNLATCH command.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the X50A fuse block-underhood.
• If the test lamp is always OFF and the B+ circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the M40 rear compartment lid latch.
• If the test lamp is always OFF and the B+ circuit fuse is normal, test the control circuit for an open/high resistance. If the circuit tests normal, refer to Underhood Fuse Block Test.
5. If all circuits test normal, test or replace the M40 rear compartment lid latch.
Underhood Fuse Block Test
1. Ignition OFF, disconnect the X1 harness connector at the X50A fuse block-underhood.
2. Test for less than 10 ohms between the ground circuit terminal 71 and ground.
• If greater than the specified range, test the ground circuit for and open/high resistance.
3. Connect the X1 harness connector at the X50A fuse block-underhood.
4. Disconnect the X5 harness connector at the K9 BCM.
5. Ignition ON, test for less than 1 V between the control circuit terminal 11 and ground
• If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the X50A fuse block-underhood.
6. Ignition ON, connect a 10 A fused jumper wire between the control circuit terminal 11 and B+. Verify the M40 rear compartment lid latch is activated.
• If the M40 rear compartment lid latch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the X50A fuse block-underhood.
7. If all circuits test normal, replace the K9 BCM.
Component Testing
Rear Compartment Lid Release Actuator
1. Ignition OFF, disconnect the harness connector at the M40 rear compartment lid latch.
2. Install a 10 A fused jumper wire between the control terminal 1 and 12 V. Momentarily install a jumper wire between the ground terminal 2 and ground. Verify the M40 rear compartment lid latch activates.
• If the actuator does not perform as specified, replace the M40 rear compartment lid latch.
Rear Compartment Lid Release Switch
1. Ignition OFF, disconnect the harness connector at the S58A rear compartment lid unlatch switch-exterior.
2. Test for infinite resistance between the signal circuit terminal 1 and the ground circuit terminal 3 with the switch in the open position.
• If not the specified value, replace the S58A rear compartment lid unlatch switch-exterior.
3. Test for less than 2 ohms between the signal circuit terminal 1 and the ground circuit terminal 3 with the switch in the closed position.
• If greater than the specified range, replace the S58A rear compartment lid unlatch switch-exterior.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Rear Compartment Lid Latch Replacement Service and Repair
* Rear Compartment Lid Release Switch Replacement Service and Repair
* Underhood Electrical Center or Junction Block Replacement Underhood Electrical Center or Junction Block Replacement
* Control Module References Programming and Relearning for BCM replacement, programming and setup