B3618

DTC B3618

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.

DTC Descriptor
DTC B3618 00
- Exterior Liftgate Unlatch Switch Circuit Malfunction

Diagnostic Fault Information






Circuit/System Description

When the ignition is ON, the body control module (BCM) supplies a signal to the rear compartment lid unlatch switch through the trunk release switch signal circuit. When the exterior rear compartment lid release switch is pressed, the voltage within the signal circuit is pulled low and in response, the BCM will energize the trunk release relay.

Conditions for Running the DTC

The system voltage is 9-16 V.

Conditions for Setting the DTC

The BCM detects a short to ground in the rear compartment lid release switch signal circuit for greater than 60 seconds

Action Taken When the DTC Sets

The BCM ignores the input from the rear compartment lid unlatch switch.

Conditions for Clearing the DTC

* This 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 Sunshade - Left (D6I)
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 Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Trunk Lid/Liftgate Window Exterior Unlatch Switch parameter while pressing and releasing the S58A rear compartment lid unlatch switch-exterior. The parameter should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the X920 inline connector at the rear license plate lamp wiring harness.
2. Test for less than 5 ohm between the ground circuit terminal 3 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 Lid/Liftgate Window Exterior Unlatch 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.

4. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 3. Verify the scan tool Trunk Lid/Liftgate Window Exterior 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 rear license plate lamp wiring harness.

Component Testing

Trunk Release Switch
1. Ignition OFF, disconnect the X920 inline connector at the rear license plate lamp wiring harness.
2. Test for infinite resistance between the signal circuit terminal 4 and the ground circuit terminal 3 with the switch in the open position.

• If not the specified value, replace the rear license plate lamp wiring harness.

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

• If greater than the specified range, replace the rear license plate lamp wiring harness.

Repair Instructions

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

* Rear License Plate Lamp Wiring Harness Replacement Rear License Plate Lamp Wiring Harness Replacement
* Control Module References Control Module References for BCM replacement, setup, and programming