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 Systems Schematics

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

1. Vehicle in Service Mode.

2. Verify the scan tool Trunk Lid/Liftgate Window Exterior Unlatch Switch parameter changes between Active and Inactive when pressing and releasing the liftgate handle switch.

• If the parameter does not change
Refer to Circuit/System Testing.

• If the parameter changes

3. All OK.

Circuit/System Testing

1. Vehicle OFF, disconnect the harness connector at the S46 liftgate handle switch. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

• If 10 ohms or greater

1. Vehicle OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

3. Vehicle in Service Mode.

4. Verify the scan tool Trunk Lid/Liftgate Window Exterior Unlatch Switch parameter is Inactive.

• If not Inactive

1. Vehicle OFF, disconnect the harness connector at the K9 body control module.

2. Test for infinite resistance between the signal circuit terminal 1 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K9 body control module.

• If Inactive

5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the ground circuit terminal 2.

6. Verify the scan tool Trunk Lid/Liftgate Window Exterior Unlatch Switch parameter is Active.

• If not Active

1. Vehicle OFF, disconnect the harness connector at the K9 body control module, Vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If Active

7. Test or replace the S46 liftgate handle switch.

Component Testing

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 less than infinite resistance
Replace the S46 liftgate handle switch.

• If infinite resistance

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

• If 3 ohms or greater
Replace the S46 liftgate handle switch.

• If less than 3 ohms

4. All OK

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