Parking Assist System - Erratic Operation
XJ413-01DATE
05/04
XJ range
MODEL
2004MY
XJ range
VIN
G00001-G18389
Front Parking Aid Operating With No
Obstruction Present - Operating
Characteristics - Revised Sensor
Issue:
On occasion, the parking aid sensors may sound a proximity warning when not expected. This bulletin provides some background information on the operating characteristics of the parking aid system.
SYSTEM OPERATION
The 4 sensors, front or rear depending on which is active, transmit an ultrasonic signal. All 4 sensors then wait for that signal to be returned. If any of the 4 sensors receive a return signal, the park aid module will operate the warning sounder. This return signal has to be sent directly back to the sensor in the same plane as the outward signal for the warning to operate.
FRONT PARKING AID
The front parking aid sensors are activated when a forward range is selected and the vehicle speed is below 9 mph (15 km/h). The system is deactivated when the vehicle speed exceeds 9 mph (15 km/h). The system is reactivated when the vehicle speed falls below 6 mph (10 km/h). The front sensors will detect an object up to a range of 32 inches (0.8 m) along the width if the vehicle and 24 inches (0.6 m) at the corners. The front parking aid sensors are also activated when reverse gear is selected. Front parking aid can be deactivated by operating the cancellation switch located in the roof console.
Note:
This also deactivates the rear parking aid sensors.
REVERSE PARKING AID
The reverse parking aid sensors are activated when reverse gear is selected. The rear sensors will detect an object up to a range of 72 inches (1.8 m) along the width of the vehicle and 24 inches (0.6 m) at the corners.
DIAGNOSTICS
When the ignition is turned to position II, the system carries out a self-check. If a fault is detected the control module will generate a fault code, a continuous warning tone will be emitted for 3.5 seconds and the system will be deactivated. Therefore unless a fault code is generated and the 3.5 sec warning heard, it should be assumed that the system is operating correctly.
SPURIOUS WARNINGS
There are some conditions that will activate the system when there is no obvious obstruction. If the vehicle is moving on loose gravel, which has a totally random surface, the sensor could receive a return signal and operate the warning. It is known that anything that emits sound waves at a frequency between 15-150 kHz may affect the sensors. Known influences include fire engine klaxons, pneumatic tools, air brakes, high performance motorcycle/auto engine exhausts. Any of these can cause the warning sounder to be activated. In harsh weather conditions, such as very heavy rainfall, the volume of water passing over the sensor can cause it to operate.
This will also happen if the sensor is covered by ice, frost or grime buildup. In none of these circumstances is there anything wrong with the system.
CONTINUOUS OPERATION OF THE FRONT SENSORS
Some markets had an issue where the front parking aid sensors operated all of the time. This cause was found to be the front inner sensors detecting the license plate bracket (plinth). This affected vehicles between VINs G00442 & G18389. In North America modified brackets were put into the vehicles at the port of entry.
The final fix, for the issue with the license plate bracket, was the introduction of a new inner sensor, part number C2C 21643XXX, introduced at VIN G18389.
When installing a license plate bracket (plinth), center the bracket between the front parking aid sensors.
Note:
Do not use any other datum points, such as the grille, to align the bracket.
To find the center line of the front spoiler on cars fitted with front parking aid sensors, measure between the two center sensors.
Align the top edge of the bracket 15 mm away from the bumper feature.
Action:
Should a customer express concern, a new modified front inner parking aid sensor should be installed in place of the inner sensor giving the proximity warning. Refer to Workshop Manual, section: 413-13, SRO 86.62.01.
Parts Information:
Warranty Information:
Warranty claims should be submitted quoting the information found in the table.
This will result in payment of the stated time and, where applicable parts/miscellaneous expense codes as listed.
Note:
The front parking aid sensor is supplied primed. For painting allowance please follow the Warranty Policy and Procedure Manual.
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