Trunk Ajar Indicator Malfunction

Trunk Ajar Indicator 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) receives a discrete input from the rear compartment lid ajar switch signal circuit. When the rear compartment lid latch releases the rear compartment lid, the rear compartment lid ajar switch, which is internal to the rear compartment lid latch, is supplied with ground which causes the trunk ajar switch signal circuit to be pulled low. The BCM interprets this and communicates via serial data to the driver information center which will display the Trunk Open message.

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

Door Ajar Indicator 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

Ignition ON, observe the scan tool Rear Closure Ajar Switch parameter while opening and closing the trunk. The parameter should change between Inactive and Active.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the M40 rear compartment lid latch.

2. Ignition ON, verify the scan tool Rear Closure Ajar Switch parameter is Inactive.

• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K9 BCM.

3. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Rear Closure Ajar Switch parameter is Active.

• If not the specified value, test the signal circuit terminal 4 for a short to voltage or and open/high resistance. If the circuit tests normal, replace the K9 BCM.

4. If all circuits test normal, test or replace the M40 rear compartment lid latch.

Component Testing

Static Test

1. Ignition OFF, disconnect the harness connector at the M40 rear compartment lid latch.

2. Test for infinite resistance between the signal terminal 4 and the ground terminal 2 with the switch in the open position.

• If not the specified value, replace the M40 rear compartment lid latch.

3. Test for less than 2 ohms between the signal terminal 4 and the ground terminal 2 with the switch in the closed position.

• If greater than the specified range, replace the M40 rear compartment lid latch.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests

* Rear Compartment Lid Latch Replacement Service and Repair

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