B2503

DTC B2503

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy 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.


DTC Descriptor
DTC B2503 00
- Trunk Key Switch Circuit



Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) monitors the trunk ajar switch circuit. The trunk ajar switch is normally open when the trunk is fully closed. When the trunk is open, the trunk ajar switch contact closes providing a path to ground. The BCM detects the drop in voltage and sends a signal to the driver information center (DIC) which displays the trunk ajar message.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Condition for Setting the DTC

When the BCM detects a short to ground in the trunk ajar switch signal circuit for longer than 10 minutes.

Action Taken When the DTC Sets

Trunk ajar lamp will be continuously illuminated.

Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 ignition cycles


Reference Information
Schematic Reference

Release Systems Schematics (Release Systems Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Door Ajar Indicator 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

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the rear compartment lid. The parameter should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the rear compartment lid latch.
2. Ignition ON, verify the scan tool Rear Closure Ajar Sw. 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 BCM.

3. Connect a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Rear Closure Ajar 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.

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


Component Testing

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 3 in the open position.

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

3. Test for less than 2 ohms between the signal terminal 1 and the ground terminal 3 in the closed position.

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



Repair Instructions

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

* Rear Compartment Lid Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming