Park Assist System - False Object Detected/False DTC's: Overview

NUMBER: 08-004-05

GROUP: Electrical

DATE: January 26, 2005

THIS BULLETIN IS BEING PROVIDED IN ADVANCE. DO NOT ORDER PARTS OR PERFORM ANY ACTIONS RELATED TO THIS BULLETIN UNTIL FEBRUARY 21, 2005.

SUBJECT:
Park Assist System - False Object Detected And Erroneous DTC's

OVERVIEW:
This bulletin involves removing the rear fascia and replacing all four Park Assist sensor spacers.

MODELS:

2005 (WK) Grand Cherokee

NOTE:
This bulletin applies to vehicles equipped with the Park Assist system (sales code XAA) and built prior to January 15, 2005 (MDH 0115XX).

SYMPTOM/CONDITION:

The customer may experience an intermittent erroneous warning (LED illumination and/or audible alarm) from the Park Assist system. When the customer places the vehicle shifter into the Reverse position, the Park Assist system may falsely indicate that an object is behind the rear of the vehicle and is within detection range of the system. One or both red LED's may be on constantly while the vehicle is in reverse. The condition may be accompanied with Park Assist system Diagnostic Trouble Codes (DTC), and a "Service Park Assist System" message may be displayed by the Electronic Vehicle Information Center (EVIC) in the instrument cluster.

DIAGNOSIS:

Normal accumulation of debris, snow, or ice (even a thin layer accumulation) on the face of the sensor may cause the above condition. Therefore it is important to first verify that the chrome faces of all four (4) rear Park Assist sensors are clean of debris, snow, and ice.

If the rear park assist sensors are clean of debris, snow, and ice, then the false object detected condition may be caused by a possible signal reflection from the rear fascia chrome applique. The sensor has a spacer to properly position it relative to the rear fascia and applique to prevent possible erroneous signal reflections. The erroneous signal reflection from the chrome applique may generate DTC's.

Verify if one or more of the following Park Assist Diagnostic Trouble Codes (DTC) are present:

^ B122F - PTS Sensor 7 Ring Time Too Long.

^ B1234 - PTS Sensor 8 Ring Time Too Long.

^ B1239 - PTS Sensor 9 Ring Time Too Long.

^ B123E - PTS Sensor 10 Ring Time Too Long.

If one or more of the above Park Assist system related DTC's have occurred and the rear sensors are known to be free of debris, snow, and ice when the condition occurs, then perform the Repair Procedure.





PARTS REQUIRED:





SPECIAL TOOLS/EQUIPMENT REQUIRED:

POLICY:
Reimbursable within the provisions of the warranty.





TIME ALLOWANCE:





FAILURE CODE:

Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.