B2503

DTC B2503

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.



DTC Descriptor
DTC B2503 00
- Trunk Key Switch Circuit




Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) uses the rear compartment lid latch to determine the position of the trunk lid. When the trunk lid is open or ajar, the rear compartment lid ajar switch is closed, providing a ground path for the trunk ajar switch signal circuit. When the BCM detects that the trunk lid is open or ajar, a serial data message is sent to the driver information center (DIC) requesting the Trunk Open message be displayed.


Conditions for Running the DTC

The system voltage is 9-18 volts.


Condition for Setting the DTC

When the BCM detects a short to voltage in the trunk ajar switch signal circuit.


Action Taken When the DTC Sets

The Trunk Open indicator will constantly illuminate on the DIC or will not illuminate when the rear compartment lid is open or ajar.


Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.



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

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

Scan Tool Reference

Programming and Relearning (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 reading should change between Inactive and Active.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector 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. Install a 3-amp fused jumper between the signal circuit terminal 1 and the ground circuit terminal 3. 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 and 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 with the switch in the open position.

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

3. Test for less than 2.0 ohms between the signal terminal 1 and the ground terminal 3 with the switch 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)
* Programming and Relearning (Programming and Relearning) for BCM replacement, setup, and programming