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Tahoe / Yukon Service Manual

Parking Assist System Malfunction

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 Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
2555 Signal — 1 — —
5852 Control 2 2 3 —
1851 Ground — 1, 2 — —
1. Parking assist cannot be disabled using the parking assist switch 2. Parking assist indicator inoperative 3. Parking assist indicator always on

Scan Tool Data Parking Assist Disable History 1–8

Control Module Data List Values Normal Operation
K182 Parking Assist Control Module Park Assist Disable History Data None, Disabled By Switch, Disabled by Customization Menu, Vehicle Speed Too High, Unknown, Vehicle Speed Invalid, Steering Angle Signal Invalid, Front Attached Object Detected, Rear Attached Object Detected, Front And Rear Attached Object Detected, Left Front Side Parking Assist Alarm Sensor Each parameter indicates a rolling history of the last 8 reasons for a park assist disable condition
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Control Module Data List Values Normal Operation
Front Outer Parking Assist Alarm Sensor Blocked, Left Front Middle Parking Assist Alarm Sensor Blocked, Right Front Middle Parking Assist Alarm Sensor Blocked, Right Front Outer Parking Assist Alarm Sensor Blocked, Right Front Side Parking Assist Alarm Sensor Blocked, Right Rear Side Parking Assist Alarm Sensor Blocked, Right Rear Outer Parking Assist Alarm Sensor Blocked, Right Rear Middle Parking Assist Alarm Sensor Blocked, Left Rear Middle Parking Assist Alarm Sensor Blocked, Left Rear Outer Parking Assist Alarm Sensor Blocked, Left Rear Side Parking Assist Alarm Sensor Blocked, Haptic Seat Malfunction, Chime Malfunction, Parking Assist Switch Malfunction, Invalid Gear, Incorrect Power Mode

Circuit/System Description The parking assist switch is part of the S48C Multifunction Switch 1 - Instrument Panel. It is a normally open switch that closes when the switch is pressed. The K9 Body Control Module monitors the switch on signal circuit 2555 and the switch receives a constant ground on ground circuit 1851. When the parking assist switch is not pressed, the switch is open and signal voltage observed by the K9 Body Control Module is high. When the parking assist switch is pressed, the switch is closed and signal voltage observed by the K9 Body Control Module is low. The parking assist indicator is part of the S48C Multifunction Switch 1 - Instrument Panel. The K9  Body Control Module control the indicator with control circuit 5852 and the indicator receives a constant ground on ground circuit 1851. When the parking assist system is enabled, the K9 Body Control Module applies PWM voltage to circuit 5852, which will illuminate the indicator. Diagnostic Aids The scan tool Parking Assist Disable History 1–8 data can be used to diagnose a malfunction within the parking assist system or an intermittent concern. The following is a brief description of potential causes which may aid in diagnosis. For each potential issue, perform an appropriate inspect of the component or system and refer to the specific service information subsection related to that system for further diagnosis: Disable by Switch – The parking assist system has been disabled through the parking assist switch. Disabled by Customization Menu – The parking assist system has been disabled through the vehicle personalization menu. Vehicle Speed Too High – The vehicle is travelling too fast in reverse at speeds of greater than 8 km/h (5 mph). Vehicle Speed Invalid – The vehicle is unable to determine the vehicle speed. Steering Angle Signal Invalid – The vehicle is unable to determine the steering angle. Front Attached Object Detected – An object has been determined to be attached to the front of the vehicle. Common items such as a brush guards, light bars, and license plates may cause this concern. Additionally, damage to the front 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). Rear Attached Object Detected – An object has been determined to be attached to the rear of 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). Front And Rear Attached Object Detected – An object has been determined to be attached to the front and rear of vehicle. Parking Assist Alarm Sensor Blocked – One of the following conditions may be present: – 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. Haptic Seat Malfunction – A fault exists with the safety alert seat. Check for DTCs. Chime Malfunction – A fault exists with the vehicle chime. Check for DTCs. Parking Assist Switch Malfunction – A fault exists with the parking assist switch. Check for DTCs. Invalid Gear – The vehicle has determine a plausibility fault exists with the transmission range. Incorrect Power Mode – The vehicle is in an incorrect power mode for parking assist operation. Reference Information Schematic Reference Parking Assistance Systems Schematics Connector End View Reference Master Electrical Component List Description and Operation Parking Assist 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.
  2. Verify the parking assist indicator turns on and off when pressing and releasing the parking assist switch. ⇒ If the parking assist indicator does not turn on and off Refer to Circuit/System Testing. ⇓ If the parking assist indicator turns on and off
  3. All OK. A fault is currently not present and may be an intermittent condition. Refer to Diagnostic Aids to identify any Parking Assist Disable History items that may be related to the customer’s concern. Circuit/System Testing
  4. Ignition OFF, disconnect the X3 connector at the K9 Body Control Module.
  5. Test for infinite resistance between signal circuit terminal 31 and ground. ⇒ If less than infinite resistance 2.1. Test circuit 2555 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 2.2. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇓ If infinite resistance
  6. Test for less than infinite resistance between signal circuit terminal 31 and ground while pressing and holding the parking assist switch. ⇒ If infinite resistance 3.1. Test circuit 1851 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If a short to ground is not found 3.2. Test circuit 2555 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 3.3. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇓ If less than infinite resistance
  7. Verify the parking assist indicator is not illuminated. ⇒ If the parking assist indicator is illuminated 4.1. Test circuit 5852 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on circuit 5852. ⇓ If a short to voltage is not found 4.2. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇓ If the parking assist indicator is not illuminated
  8. Connect a 3 A fused jumper wire between control circuit terminal 14 and B+.
  9. Verify the parking assist indicator is illuminated. ⇒ If the parking assist indicator is not illuminated 6.1. Test circuit 5852 for a short to ground. ⇒ If a short to ground is found, repair the fault on circuit 5852. ⇓ If a short to ground is not found 6.2. Test circuit 5852 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on circuit 2555. ⇓ If an open/high resistance is not found 6.3. Replace the S48C Multifunction Switch 1 - Instrument Panel. ⇓ If the parking assist indicator is illuminated
  10. Replace the K9 Body Control Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Parking Assistance Systems Component Replacement Reference Control Module References for control module replacement, programming, and setup.