For 1990-2009 cars

## Object Detection System Malfunction Holden Genuine Accessory

### Diagnostic Instructions

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

• | Review Strategy Based Diagnosisfor an overview of the diagnostic approach.

• | Diagnostic Procedure Instructionsprovides an overview of each diagnostic category Circuit/System Description.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Object Alarm Module 12-Volt Control Circuit | 1, 4 | 1, 4 | 2, 4 | --
Object Alarm Module Ground | -- | 1, 3, 4 | 1, 3, 4 | --
Object Alarm Sensor 8-Volt reference | 4, 5 | 4, 5 | 4, 5 | --
Object Alarm Sensor Low Reference | -- | 4, 5 | 4, 5 | --
Object Alarm Indicator 8-Volt reference | 4, 6 | 4, 6 | 4, 6 | --
Object Alarm Control Circuit | 4, 7 | 4, 6 | 4, 6 | --
1. Backup Lamps Inoperative. 2. Backup Lamps Always ON. 3. Park Lamps Inoperative. 4. Rear Object Detection System Inoperative. 5. Object Alarm Sensor Inoperative.

6. Object Alarm Indicator Inoperative.

7. Object Alarm Indicator Always ON.

### Circuit/System Description

The object alarm module supplies 8 volts to the object alarm sensors through the reference/signal circuit and provides ground through the low reference circuit. Each sensor emits an ultrasonic frequency which is reflected off object located behind the vehicle. These reflections are received by the sensors. The time difference between when the frequency was emitted and when the reflection is received is known as sensor ring time. The object alarm module uses the sensor ring time, which is received through the reference/signal circuit to calculate the distance and position of an object. The object alarm module supplies 8 volts to the object alarm indicator through the 8-volts reference circuit and ground through the control circuit. The buzzer sound produced by the object alarm indicator indicates how close the vehicle rear bumper is to an object.

### Diagnostic Aids

The following is a brief description of potential causes which may aid in diagnosis:

Important: The recommended vehicle reversing speed is below five kph.

• | Attached Object- The object alarm module is detecting an object that is attached to the vehicle. Common items such as trailer, caravan or a bicycle rack may cause this concern.

• | Trailer plug connector - If the vehicle is fitted with a genuine Holden trailer harness, opening the trailer connector cover actuates a switch that disables the rear object detection system. Damage to the trailer connector or to the trailer connector cover may disable the object detection system. Refer to Trailer Connector/Provision Component Views Trailer Connector/Provision Description and Operation.

• | Sensor Alignment - damage to the rear of the vehicle or a misaligned sensor may cause this concern. If the vehicle is damaged in a manner that causes the sensor to detect the bumper itself, the object alarm indicator will produce continuous buzzer sound. Carefully inspect the bumper, bumper mounting surface, and sensor retainers before continuing with normal diagnosis.

• | Sensor Disturbance - An outside interference is causing sensor movement. Such interference may be caused a heavy pounding, like that of a nearby jackhammer, or large changes in pressure, such as a large truck's air brakes.

• | Snow/Ice/Mud - One or more of the sensors is being blocked by snow, mud, ice, or other debris.

• | Sensor Ring Time - Each of the sensors emits an ultrasonic frequency. This frequency is reflected off of nearby objects, bouncing it back towards the vehicle bumper where it is received by the sensor. The time between the sensor emitting the frequency and the sensor receiving the reflection, known as sensor ring time, is used to determine the distance of nearby objects. Paint on a sensor may cause an excessive sensor ring time. Make sure the sensors are not painted.

### Reference Information

#### Schematic Reference

Object Detection Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Object Detection Description and Operation

#### Component View Reference

Object Detection Component Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

1. Ignition ON, engine OFF, Park brake ON, Transmission in REVERSE, verify that the reverse lights illuminate.

⇒ | If inoperative, inspect the backup lamps, backup lamp fuse or the backup lamp switch.

2. Ignition ON, engine OFF, park brake ON, transmission in REVERSE, individually place a suitable object behind each sensor. Verify the correct operation of each sensor.

### Circuit/System Testing

1. Ignition OFF, disconnect the X1 connector at the Object Alarm Module.
2. Test for less than 1.0 ohm between the ground circuit terminal 2 X1 and ground.

⇒ | If greater than the specified value, test the ground circuit for an open/high resistance.

3. Ignition ON, engine OFF, park brake ON, transmission in REVERSE, verify that a test lamp illuminates between the object alarm module signal circuit terminal 1 X1 and ground.

⇒ | If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance.

4. Ignition OFF, connect the X1 connector at the object alarm module.
5. Ignition OFF, disconnect the harness connector at the appropriate object alarm sensor.
6. Test for less than 1 ohm between the low reference circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance.

⇒ | If the circuit tests normal, replace the object alarm module.

7. Ignition ON, engine OFF, Park brake ON, transmission in REVERSE, test for 7.5-8.5 volts between the reference circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the voltage reference circuit for a short to voltage.

⇒ | If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance.

⇒ | If the circuit tests normal, replace the object alarm module.

### Repair Instructions

For component removal and installation refer to the accessory fitting instructions. Perform the Diagnostic Repair Verificationafter completing the diagnostic procedure.