B153F

DTC B153F

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B153F 05
- Liftgate Object Sensor Signal Circuit Voltage Below Threshold

DTC B153F 07
- Liftgate Object Sensor Signal Circuit Voltage Above Threshold

Diagnostic Fault Information






Circuit/System Description

The liftgate object sensor uses two tape switches embedded in the liftgate opening weatherstrip to detect any foreign objects in the path of the liftgate. When pressure is applied to the weatherstrip, the tape switch is closed signaling the liftgate module (LGM) that an object is in the path of the liftgate. The LGM will reverse the direction of the liftgate motor should this occur.

The 2 tape switches are placed in series between the liftgate object sensor signal circuit and the liftgate object low reference circuit. Each object sensor has a resistor as well as a switch. The resistors enable the LGM to perform diagnostic functions on the circuits. When both switches are open, voltage supplied by the LGM passes through the resistors and supplies the LGM with a reference voltage. If an object is in the path of the moving liftgate, the affected switch would close. The closing of the switch would bypass the resistor and change the reference voltage seen by the LGM, indicating that one of the switches is closed and an object has been detected.

Conditions for Running the DTC

The system voltage is 9-18 volts.

Conditions for Setting the DTC

B153F 05

When the LGM detects less than 3 volts in the liftgate tape switch signal circuit.

B153F 07

When the LGM detects greater than 5.5 volts in the liftgate tape switch signal circuit.

Action Taken When the DTC Sets

The power liftgate will be inoperative until the conditions for setting the DTC are no longer present. If the liftgate is in motion prior to the DTC setting, the liftgate will close and immediately re-open.

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 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.

Circuit/System Verification

Ignition ON, observe the scan tool Object Sensor Supply Voltage parameter while pressing and depressing the appropriate liftgate object sensor. The parameter should change between Inactive and Active.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the left and right liftgate object sensors.
2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal A and ground at the left liftgate object sensor harness connector.

^ If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the LGM.

3. Ignition ON, test for 4.75 to 5.25 volts between the signal circuit terminal B and ground at the right liftgate object sensor harness connector.

^ If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the LGM.

^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the LGM.

4. Ignition OFF, test for infinite resistance between the left/right object sensor signal circuit terminal A and ground.

^ If less than the specified range, test the signal circuit for a short to ground

5. If all circuits test normal, test or replace the appropriate liftgate object sensor.

Component Testing

1. Ignition OFF, disconnect the harness connector at the right liftgate object sensor.
2. Test for 10K ohms of resistance between the signal terminal A and the low reference terminal B.

^ If not within the specified range, replace the right liftgate object sensor.

3. Disconnect the harness connector at the left liftgate object sensor.
4. Test for 10K ohms of resistance between the signal terminal A and the low reference terminal B.

^ If resistance is not within the specified range, replace the left liftgate object sensor.

Repair Instructions

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