Parking Assist System Malfunction
Parking Assist System Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The parking assist system is enabled and disabled through the parking assist switch. When enabled, the parking assist indicator will illuminate.
For vehicles without UGN, the switch and indicator are connected to the Parking Assist Control Module. The Parking Assist Control Module supplies a reference voltage to the parking assist switch. When the switch is pressed, the signal circuit is grounded. The Parking Assist Control Module can control the Park Assist Indicator by grounding the control circuit to illuminate the LED which indicates that the system is enabled.
With UGN, the indicator and switch are connected to the Active Safety Control Module. The Active Safety Control Module receives input from several modules including the Parking Assist Control Module to provide additional features. Refer to Object Detection Description and Operation (with Active Safety System - UGN) Object Detection Description and Operation (with Active Safety System - UGN)Object Detection Description and Operation (with rear vision camera - UVC) Object Detection Description and Operation (with rear vision camera - UVC)Object Detection Description and Operation (with front and rear park assist - UD5) Object Detection Description and Operation (With Front and Rear Park Assist - UD5)Object Detection Description and Operation (with rear park assist - UD7) Object Detection Description and Operation (With Rear Park Assist - UD7)Object Detection Description and Operation (with side blind zone alert - UFT) Object Detection Description and Operation (with side blind zone alert - UFT)Object Detection Description and Operation (with rear cross traffic alert - UFG) Object Detection Description and Operation (With Rear Cross Traffic Alert - UFG)Object Detection Description and Operation (with lane departure warning - UFL) Object Detection Description and Operation (With Lane Departure Warning - UFL)Object Detection Description and Operation (with forward collision alert - UEU) Object Detection Description and Operation (With Forward Collision Alert - UEU)Object Detection Description and Operation (with Haptic Signal Motor Seat) Object Detection Description and Operation (with Haptic Signal Motor Seat) for additional information on UGN. The parking assist alerts and DTCs are from the Parking Assist Control Module with the exception of the indicator DTCs which are sent by the Active Safety Control Module. There are no switch DTCs for vehicles with the Active Safety Control Module.
The Parking Assist Control Module supplies an 8V reference voltage and a low reference to the object sensors. The sensors will return a signal based on the reflections from objects within range of the sensors.
When an object is detected, the Parking Assist Control Module will send serial data to the radio and memory seat module to provide either an audible alert or haptic feedback through the Active Safety Seat. The driver can select between audible or haptic alerts in the vehicle personalization menu.
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 through the parking assist switch or audio system personalization menu.
* Hitch/Object Attached - The parking assist control 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 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 parking assist control 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. After the detected cause has been addressed the vehicle must be driven at speed greater than 40 km/h (25 mph).
* Reverse Overspeed - The vehicle is travelling too fast in reverse at speeds of greater than 8 km/h (5 mph).
* Inhibit - The parking assist control module has lost or received invalid GMLAN signal(s).
* 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 air brakes.
* Sensor Ring Time - If the sensor fails its own diagnostic initialization the parking assist control module will set this error. After the detected cause has been addressed the vehicle must be driven at speed greater than 40 km/h (25 mph). The following is a list of reasons this cause may have set:
- One or more of the sensors may be blocked by snow, mud, ice, or other debris. This might happen after going through a car wash in cold weather.
- Silicone insulator surrounding sensor maybe missing, cut, or twisted.
- Improperly installed sensor, sensor maybe be crooked due to a tight wire harness.
- One or more of the sensors may be scratched or the paint maybe chipped.
- 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 [1][2]Collision Avoidance and Parking Assist Systems
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Object Detection Description and Operation (with Active Safety System - UGN) Object Detection Description and Operation (with Active Safety System - UGN)Object Detection Description and Operation (with rear vision camera - UVC) Object Detection Description and Operation (with rear vision camera - UVC)Object Detection Description and Operation (with front and rear park assist - UD5) Object Detection Description and Operation (With Front and Rear Park Assist - UD5)Object Detection Description and Operation (with rear park assist - UD7) Object Detection Description and Operation (With Rear Park Assist - UD7)Object Detection Description and Operation (with side blind zone alert - UFT) Object Detection Description and Operation (with side blind zone alert - UFT)Object Detection Description and Operation (with rear cross traffic alert - UFG) Object Detection Description and Operation (With Rear Cross Traffic Alert - UFG)Object Detection Description and Operation (with lane departure warning - UFL) Object Detection Description and Operation (With Lane Departure Warning - UFL)Object Detection Description and Operation (with forward collision alert - UEU) Object Detection Description and Operation (With Forward Collision Alert - UEU)Object Detection Description and Operation (with Haptic Signal Motor Seat) Object Detection Description and Operation (with Haptic Signal Motor Seat)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the park assist system is enabled through the parking assist switch.
• If the park assist system is not enabled
Refer to the vehicle owners manual for instructions on enabling the system.
• If the park assist system is enabled
3. Verify 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 Active and Inactive
Refer to Circuit/System Testing - Parking Assist Switch Circuit Malfunction.
• If the parameter changes between Active and Inactive
4. 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 Circuit/System Testing - Parking Assist Switch Indicator Circuit Malfunction.
• If the indicator does turn ON and OFF
5. Transmission in R, verify the Engine Control Module (ECM) scan tool Reverse Position Switch parameter is Active.
• If the parameter is not Active
Refer to Backup Lamps Malfunction Backup Lamps Malfunction.
• If the parameter is Active
6. Transmission in R, verify the scan tool Park Assist System Status parameter displays Enable.
• If the parameter is not Enabled
Refer to Diagnostic Aids to determine the cause of the inhibit.
• If the parameter is Enabled
7. All OK.
Circuit/System Testing (without UGN)
Parking Assist Switch Circuit Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Parking Assist Switch Status parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the X1 harness connector at the K41 Parking Assist Control Module.
2. Test for infinite resistance between the control circuit terminal 8 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K41 Parking Assist Control Module.
• If Inactive
5. Install a 3 A fused jumper wire between the signal circuit terminal 8 and the ground circuit terminal 5.
6. Verify the scan tool Parking Assist Switch Status parameter is Active.
• If not Active
1. Ignition OFF, disconnect the X1 harness connector at the K41 Parking Assist Control Module.
2. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K41 Parking Assist Control Module.
• If Active
7. Replace S48D Multifunction Switch 2 - Instrument Panel.
Parking Assist Switch Indicator Circuit Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the S48D Multifunction Switch 2 - Instrument Panel, Ignition ON.
2. Verify a test lamp illuminates between the ignition circuit terminal 1 and ground.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the ignition circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms , replace the K9 Body Control Module.
• If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 2 and the ignition circuit terminal 1.
4. Verify the lamp turns ON and OFF when commanding the Park Assist Switch Indicator ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X1 harness connector at the K41 Parking Assist Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF.
4. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K41 Parking Assist Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the X1 harness connector at the K41 Parking Assist Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K41 Parking Assist Control Module.
• If the test lamp turns ON and OFF
5. All OK.
Circuit/System Testing (with UGN)
Parking Assist Switch Malfunction
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Park Assist Switch parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the harness connector X1 at the K124 Active Safety Control Module.
2. Test for infinite resistance between the signal circuit terminal 11 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K124 Active Safety Control Module.
• If Inactive
5. Install a 3 A fused jumper wire between the signal circuit terminal 11 and the ground circuit terminal 5.
6. Verify the scan tool Park Assist Switch parameter is Active.
• If not Active
1. Ignition OFF, disconnect the harness connector at the K124 Active Safety Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K124 Active Safety Control Module.
• If Active
7. Test or replace the S48D Multifunction Switch 2 - Instrument Panel.
Parking Assist Switch Indicator Malfunction
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel. It may take up to 2 minutes for all vehicle systems to power down. Ignition ON, interior dimming set to full bright.
2. Verify a test lamp illuminates between the control circuit terminal 2 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K124 Active Safety Control Module.
• If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 2 and the control circuit terminal 3.
4. Verify the test lamp turns ON and OFF when commanding the Parking Assist Switch Indicator ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K124 Active Safety Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1V
3. Ignition OFF.
4. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms replace the K124 Active Safety Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K124 Active Safety Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K124 Active Safety Control Module.
• If the test lamp turns ON and OFF
5. Test or replace the S48D Multifunction Switch 2 - Instrument Panel.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Interior Lamp and Multifunction Switch Replacement Interior Lamp and Multifunction Switch Replacement
* Control Module References Control Module References for Parking Assist Control Module replacement, programming and setup.