B153B

DTC B153B

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 B153B 02
- Liftgate Open Switch Signal Circuit Short to Ground

DTC B153B 05
- Liftgate Open Switch Signal Circuit Open

Diagnostic Fault Information





Circuit/System Description

The full open switch is part of the gear motor assembly and will close and become active when the liftgate reaches the full open position. The full open switch signal circuit is supplied battery voltage through a resistor and monitored within the liftgate control module. The liftgate control module (LGM) provides a low reference circuit and when the switch contacts close, the signal circuit goes low and the LGM determines the switch to be active.

Conditions for Running the DTC

* The system voltage is 9-16 volts.
* Power open or close operation is attempted.

Conditions for Setting the DTC

The LGM detects a short to ground in the full open switch signal circuit.

Action Taken When the DTC Sets

The power liftgate will not power close.

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

Important: Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power (Procedures) for the appropriate procedure.


Whenever the LGM loses power or is disconnected, the ignition must be cycled OFF then ON in order to reactivate the LGM.

Reference Information
Schematic Reference

Liftgate Schematics (Liftgate Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Rear Hatch/Gate Description and Operation (Rear Hatch/Gate 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

Programming and Relearning (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool LGM Full Open Switch parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.

Circuit/System Testing

1. Ignition OFF, disconnect the X3 harness connector at the LGM.
2. Ignition ON, verify the scan tool LGM Full Open Switch parameter is Inactive.

• If not the specified value, replace the LGM.

3. Liftgate OPEN, test for less than 1 ohm between the signal circuit terminal 5 and the ground circuit terminal 6.

• If greater than the specified range, replace the liftgate motor assembly.

4. Liftgate CLOSED, test for infinite resistance between the signal circuit terminal 5 and the ground circuit terminal 6.

• If less than the specified value, replace the liftgate motor assembly.

5. If all circuits test normal, replace the LGM.

Repair Instructions

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

* Liftgate Actuator Replacement (Liftgate Actuator Replacement)
* Control Module References (Programming and Relearning) for LGM replacement, setup and programming