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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Parking Assist Switch Signal | B0967 02 | 1 | 1 | --
Parking Assist Switch Indicator Control | B0968 06 | B0968 06 | B0968 01 | --
Parking Assist Switch Ground | -- | B0968 06 | -- | --
1. Parking Assist Switch Malfunction

### Circuit/System Description

The ultrasonic parking assist system is designed to identify and notify the driver of an object in the vehicle's path when moving forward or reversing at speeds of less than 8 km/h (5 MPH). The distance and location of the object is determined by eight object sensors: four located in the rear bumper and four located in the front bumper. The parking assist system will notify the driver using an audible signal through the radio.

### Diagnostic Aids

The scan tool Park Assist Disable History parameters are a list of the seven previous reasons the parking assist system was disabled. These parameters may help in the diagnosis of an intermittent concern or a customer concern which is the result of normal system operation. The following is a brief description of potential causes which may aid in diagnosis:

• | Manual Disable - The parking assist system has been disabled by the vehicle operator through the parking assist switch.

• | Park Brake - The vehicle parking brake is applied or a malfunction exists within the parking brake system.

• | Hitch/Object Attached - The object alarm module is detecting an object that is attached to the vehicle. Common items such as a hitch receiver, trailer, or a bicycle rack may cause this concern. Additionally, damage to the front or 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 module will interpret this as an attached object and disable the system. Carefully inspect the bumper, bumper mounting surface, and sensor retainers before continuing with normal diagnosis.

• | Vehicle Overspeed - The vehicle is travelling too fast at speeds of greater than 8 km/h (5 MPH).

• | 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. Excessive paint thickness on a sensor may cause an excessive sensor ring time. When replacing or refinishing a sensor, do not apply an excessive amount of paint or clear coat.

### Reference Information

#### Schematic Reference

Object Detection Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Object Detection 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

1. Ignition ON, verify the park assist system is enabled through the parking assist switch.

⇒ | If the park assist system is manually disabled, enable the system. Refer to the vehicle owners manual for instructions on enabling the system.

2. Observe the scan tool Park Assist Switch parameter while pressing and releasing the parking assist switch. The parameter should change between Active and Inactive.

⇒ | If the parameter does not change between the specified values, refer to Parking Assist Switch Circuit Malfunction.

3. Command the Park Assist Switch LED output control ON and OFF with the scan tool. The parking assist switch indicator should turn ON and OFF when changing between the commanded states.

⇒ | If the indicator does not turn ON and OFF, refer to Parking Assist Switch Indicator Circuit Malfunction.

4. Vehicle in reverse, verify the Engine Control Module (ECM) scan tool Reverse Switch parameter is Active.

⇒ | If not the specified value, refer to Backup Lamps Malfunction

5. Vehicle in reverse, verify the scan tool Park Assist System Status parameter is Enable.

⇒ | If not the specified value, refer to Diagnostic Aids and the scan tool Park Assist Disable History parameters to determine the cause of the inhibit.

6. If all tests normal, replace the K41 Object Alarm Module.

### Circuit/System Testing

#### Parking Assist Switch Circuit Malfunction

1. Ignition OFF, disconnect the X3 harness connector at the K41 Object Alarm Module and the X1 harness connector at the S48D Multifunction Switch - I/P 2.
2. Test for less than 5 Ω between the S48D Multifunction Switch - I/P 2 ground circuit terminal 2 (X1) and ground.

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

3. Ignition ON, test for less than 0.3 V between the signal circuit terminal 8 (X3) at the K41 Object Alarm Module harness connector and ground.

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

4. Ignition OFF, connect the harness connector at the S48D Multifunction Switch - I/P 2.
5. Ignition ON, verify that a test lamp does not illuminate between the B+ circuit terminal 2 (X3) at the K41 Object Alarm Module harness connector and signal circuit terminal 8 (X3).

⇒ | If the test lamp illuminates, test signal circuit for a short to ground. If the circuit tests normal, replace the S48D Multifunction Switch - I/P 2.

6. Verify that the test lamp illuminates between the B+ circuit terminal 2 (X3) at the K41 Object Alarm Module harness connector and signal circuit terminal 8 (X3) while pressing the parking assist switch.

⇒ | If the test lamp does not illuminate, test the signal circuit for an open/high resistance. If all circuits test normal, replace the S48D Multifunction Switch - I/P 2.

7. If all circuits test normal, replace the K41 Object Alarm Module.

#### Parking Assist Switch Indicator Circuit Malfunction

1. Ignition OFF, replace the S48D Multifunction Switch - I/P 2.
2. Ignition ON, command the Park Assist Switch LED output control ON and OFF with the scan tool. The parking assist switch indicator should turn ON and OFF when changing between the commanded states.

⇒ | If the indicator does not turn ON and OFF, replace the K41 Object Alarm Module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear Object Alarm Module Switch Replacement

• | Control Module References for object alarm module replacement, setup and programming