Diagnostic Aids
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When the "PARK ASST BLOCKED SEE OWNERS MANUAL" or "PARK ASSIST BLOCKED SEE OWNERS MANUAL" message is displayed in the DIC the disable reason is stored in the Park Assist Disable History.
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 table is a brief description of potential causes and corrective action which may aid in diagnosis:
| History Buffer | Conditions That Cause This | Operating as Designed | Action Required | Corrective Action |
|---|---|---|---|---|
| Ring Down Time too long | One or more of the sensors may be covered or in contact with snow, mud, ice, frost or other debris. Also, frost or ice can form around and behind the sensors and may not always be seen. Typical example is going through a car wash in cold weather leaving a thin coat of ice between sensor and bezel/fascia. | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. Remove snow, mud, ice, frost or other debris from sensor and bezel/fascia especially in the area around the sensor near the bezel/fascia. |
| Bezel not fully seated and tabs not extended applying pressure on sensor causing misalignment and allowing the front surface of sensor to come in contact with Fascia/Bezel | No | Yes | Verify that bezel locking tabs are fully engaged | |
| Bezel/retainer coming in contact with Sensor face | No | Yes | Reposition sensor and align it to center of bezel or retainer. | |
| Damaged to bezel or retainer | No | Yes | Replace Bezel/retainer | |
| Silicone insulator surrounding sensor maybe missing, cut, or twisted. | No | Yes | Replace sensor insulator ring if damaged. | |
| One or more of the sensors may be scratched, the paint maybe chipped or excessive paint on sensor that is greater than 6 mils thickness. | No | Yes | Replace sensor. Refer to Rear Parking Assist Alarm Sensor Replacement procedure below. | |
| Improperly installed sensor, sensor maybe be crooked due to a tight wire harness. | No | Yes | Re-install sensor and correct harness strain on sensor. | |
| Out of round or jagged hole in fascia causing mechanical contact with painted surface of sensor | No | Yes | Make repair to fascia by removing any mechanical contact between fascia and painted surface of sensor | |
| Sensor fell out of retainer/bezel with sensor point toward ground or inside rear of bumper/fascia | No | Yes | Re-install sensor and verify sensor is centered in bezel/retainer. | |
| Reverse Overspeed | Driving greater than 5 mph (8 kph) in reverse | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. |
| Sensor Disturbance | An outside interference is causing sensor movement. Such interference may be caused by a heavy pounding, like that of a nearby jackhammer, or large changes in pressure, such as a large truck's air brakes. | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. |
| Manual Disable | Customer manually turning off system with the Park Assist switch | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. |
| Attached Object | Trailer, Tow bar or bike rack installed | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. Remove attached object. |
| Incorrectly installed license plate | No | Yes | Straighten or reposition license plate. | |
| Lowered tailgate or objects extending beyond a lowered tailgate or past rear of fascia. | Yes | Yes | Explain normal operation to customer. Refer to Owner's manual for normal operation. Raise tailgate or remove objects | |
| 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 module will interpret this as an attached object and disable the system. | No | Yes | Carefully inspect the bumper, bumper mounting surface, and sensor retainers before continuing with normal diagnosis | |
| Invalid Signal | The object alarm module has lost or received invalid GMLAN signal(s). | Yes | No | Check for U-codes or ECU related DTC's. No sensor replacement is needed |