Vehicle Access (TB4)
DTC B2494 (TB4)
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 B2494 00
- Liftgate Handle Switch Circuit
Diagnostic Fault Information
Circuit/System Description
The BCM supplies a 12V signal to the signal circuit of the exterior liftgate handle switch and when the release switch is activated the signal circuit voltage goes low. The BCM controls the liftgate release actuator through the liftgate latch release relay. When the release switch signal is activated, the BCM enables the liftgate latch release relay by applying battery voltage to the liftgate latch release relay supply circuit and the relay is energized when the BCM grounds the liftgate latch release relay control circuit. When the relay is energized battery voltage is supplied to the liftgate release actuator through the liftgate release actuator control circuit.
Conditions for Running the DTC
The system voltage is 9-18 V.
Conditions for Setting the DTC
The liftgate release switch signal circuit is active for greater than 30 seconds.
Action Taken When the DTC Sets
The BCM will ignore the signal from the exterior liftgate handle switch.
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.
Diagnostic Aids
Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power Service and Repair for the appropriate procedure.
If the vehicle has a history of the liftgate opening unexpectedly, inspect the point where the wires enter the exterior liftgate handle switch for corrosion or evidence of water intrusion.
Reference Information
Schematic Reference
Release Systems Schematics Release Systems Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left Front
Description and Operation
Rear Hatch/Gate Description and Operation Rear Hatch/Gate
Electrical Information Reference
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Circuit Testing Circuit Testing
* Wiring Repairs Wiring Repairs
* Connector Repairs Connector Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the operation of the liftgate when commanding the liftgate latch to UNLATCH with the liftgate handle switch.
• If the liftgate latch does not UNLATCH
Refer to Circuit/System Testing
• If the liftgate does UNLATCH
3. All OK.
Circuit/System Testing
1. Ignition 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. Ignition 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. Ignition ON.
4. Test for greater than 10 V between the signal circuit terminal 1 and ground.
• If 10 V or less
1. Ignition OFF, disconnect the X6 harness connector at the K9 body control module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance on the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If greater than 10 V
5. Test or replace the S46 liftgate handle switch.
Component Testing
Liftgate Release Switch
1. Ignition 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 repair.
* Liftgate Release Switch Replacement Liftgate Release Switch Replacement
* Control Module References Programming and Relearning for BCM replacement, setup and programming