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 vehicle is in service mode, the body control module (BCM) supplies a signal to the liftgate handle switch through the rear closure handle switch open signal circuit. When the liftgate handle switch is pressed, the voltage within the signal circuit is pulled low and in response, the BCM will energize the liftgate 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 closure handle switch open signal circuit for greater than 60 seconds

Action Taken When the DTC Sets

The rear hatch will not open when the liftgate handle switch is pressed.

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

Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation

Rear Hatch/Gate Description and Operation Rear Hatch/Gate
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

Vehicle in Service Mode, observe the scan tool Trunk Lid/Liftgate Window Exterior Unlatch Switch parameter while pressing and releasing the S46 liftgate handle switch. The parameter should change between Active and Inactive each time the switch is pressed and released.

Circuit/System Testing

1. Vehicle OFF, disconnect the harness connector at the S46 liftgate handle switch.
2. Test for less than 10 ohm between the ground circuit terminal 2 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Vehicle in Service Mode, verify the scan tool Trunk Lid/Liftgate Window Exterior 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 the ground circuit terminal 2. 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 S46 liftgate handle switch.

Component Testing

Trunk Release Switch
1. Vehicle OFF, disconnect the harness connector at the S46 liftgate handle switch.
2. Test for infinite resistance between the signal terminal 1 and the ground terminal 2 with the switch in the open position.

• If not the specified value, replace the S46 liftgate handle switch.

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

• If greater than the specified range, replace the S46 liftgate handle switch.

Repair Instructions

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

* Liftgate Release Switch Replacement Liftgate Release Switch Replacement
* Control Module References Programming and Relearning for BCM replacement, programming and setup