For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | 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 02: Liftgate Object Sensor Signal Circuit Short to Ground
DTC B153F 03: Liftgate Object Sensor Signal Circuit Voltage Below Treshold
DTC B153F 05: Liftgate Object Sensor Signal Circuit Short to Battery or Open
DTC B153F 07: Liftgate Object Sensor Signal Circuit Voltage Above Threshold

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Liftgate Module B+ | B153A 08, B396A 02 | B153A 08, B396A 02 | -- | --
Liftgate Module B+ | U0230 00 | U0230 00 | -- | --
Liftgate Position Sensor 5V Reference Voltage | B153E 02 | B153B 08 | 2 | B1019 00
Full Open Signal | B153E 08 | B153B 05 | 2 | --
Liftgate Disable Signal | 1, 2 | 1 | 1 | --
Liftgate Open Signal | 1 | 1 | 1 | --
Object Sensors Signal | B153F 02 | B153F 05 | B153F 05 | B153F 03, B153F 07
Open/Close Switches Signal | B2494 02 | 1, 2 | 1, 2 | --
Pawl Switch Signal | B153A 00 | B153A 08 | B153A 00 | B153A 08
Position Sensor Signal 1 | B153E 08 | B153E 08 | B153E 05 | --
Position Sensor Signal 2 | B153E 08 | B153A 08 | B153E 05 | B153E 08
Ratchet Switch Signal | B153A 00 | B153A 08 | B153A 00 | B153A 08
Sector Switch Signal | B153A 00 | B153A 00 | B153A 00 | B153A 08
Disengage Clutch Control | B396B 02 | B396B 04 | B396B 01 | --
Engage Clutch Control | B396B 02 | B396B 04 | B396B 01 | --
Liftgate Latch Cinch Control | B2495 02 | B2495 04 | B2495 01 | --
Liftgate Latch Release Control | B2495 02 | B2495 04 | B2495 01 | --
Liftgate Motor Close Control | B396A 02 | B396A 04 | B396A 01 | B153E 08
Liftgate Motor Open Control | B396A 02 | B396A 04 | B396A 01 | B153E 08
Full Open Low Reference | -- | B153B 05 | 2 | --
Liftgate Switches Low Reference | -- | B153A 08 | 1 | B153E 08
Position Sensor Low Reference | -- | B0153E 08 | 2 | --
I/P Switch Ground | -- | 1 | 1 | --
Liftgate Control Module Ground | -- | U0230 00 | 2 | --
1. Liftgate Switch Malfunction 2. Liftgate Malfunction

### 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 9-16 volts.

### Conditions for Setting the DTC

#### B153F 02

When the LGM detects a short to ground in the liftgate tape switch signal circuit.

#### B153F 03

When the LGM detects less than 3.3 volts in the liftgate tape switch signal circuit.

#### B153F 05

When the LGM detects a short to voltage or an open/high resistance 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.

### Reference Information

#### Schematic Reference

Liftgate Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Rear Hatch/Gate Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, observe the scan tool Object Sensor Supply Voltage parameter while pressing and releasing the left and right liftgate object sensors. The parameter should change between Inactive and Active.

### Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the LGM.
2. Test for infinite resistance between the signal circuit terminal 8 and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground.

3. Test for 15K - 25K ohms between the signal circuit terminal 8 and the low reference circuit terminal 16.

⇒ | If not within the specified range, test the signal circuit between the left and right liftgate object sensors and the low reference circuit for an open/high resistance. If the circuits test normal, test or replace the left or right liftgate object sensor.

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

### Component Testing

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

⇒ | If not within the specified value, replace the right liftgate object sensor.

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

⇒ | If not within the specified value, replace the left liftgate object sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for LGM replacement, setup and programming