For 1990-2009 cars

## Rear Park Assist Inoperative Genuine Accessory

### Diagnostic Fault Information

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

### Circuit/System Description

The rear park assist system (RPA) is designed to assist the driver when reversing and should not be used as a substitute for safe driving practices. The RPA is equipped with a module, a warning buzzer and ultrasonic sensors. The ultrasonic sensors operate both as transmitters and receivers of ultrasonic signals. The driver is alerted to approaching objects by a sequence of pulses or continuous tones from the warning buzzer.

### Reference Information

#### Schematic Reference

Object Detection Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Testing

Important: The warning buzzer component testing should be performed prior to circuit/system testing.

1. Ignition ON, engine OFF, select reverse and verify that the reverse lights illuminate.

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

2. Ignition OFF, disconnect the external relay.
3. Verify that a test lamp does not illuminate between the control circuit terminal 2 and ground.

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

4. Ignition ON, engine OFF, select reverse, verify that a test lamp illuminates between the external relay reverse control circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, test the external relay reverse control circuit terminal 1 for a short to ground or an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test or replace the external relay.

6. Ignition OFF, disconnect the RPA module harness connector X1.
7. Ignition ON, engine OFF, connect a 2-A fused jumper wire between the external relay B+ circuit terminal 1 and the external relay control circuit terminal 2. Verify that a test lamp illuminates between the RPA module harness connector X1-2 and ground.

⇒ | If test lamp does not illuminate, refer to the installation instructions and verify the correct patch harness is used or test the external relay control circuit 2 for a short to ground or an open/high resistance.

8. Connect a test lamp between the B+ terminal 5 and the ground terminal 3. Verify that the test lamp turns ON. If the test lamp is always OFF:

• | Verify that the 7-pin trailer connector micro-switch is functional and that the dust cover is closed.

• | Test the external relay ground circuit for an open/high resistance. If all circuits test normal, replace the external relay.

9. Test for less than 1.0 Ohm resistance between the RPA module harness connector X1-1 and ground.

⇒ | If greater than the specified value, refer to the installation instructions and verify the correct patch harness is used or test the ground circuit for an open/high resistance. If the circuit tests normal, replace the RPA module.

### Component Testing

#### Warning Buzzer Function Test

1. Verify that the warning buzzer is inoperative.
2. Visibly inspect the warning buzzer disable switch and ensure that the warning buzzer is not disabled.
3. Ignition OFF, disconnect the RPA module harness connector X1.
4. Connect a ground to terminal X1-3 and a B+ voltage supply to terminal X1-4. The warning buzzer should sound continuously.

⇒If not a continuous tone, replace the warning buzzer.

### Repair Instructions

For component removal and installation refer to the accessory fitting instructions.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.