2002 Jaguar XJ8 back-up parking sensors

TINMANTAM

MEMBER
2002 JAGUAR XJ8
V8
2WD
AUTOMATIC
70,000 MILES

I own 2 vehicles with back-up sensors, a Ford SUV and the Jag XJ. The Ford sensors are fine but the Jags beep almost as soon as you put it in reverse even with nothing but pavement behind it! There are 4 sensors at the rear of the car, do they work independently of each other and what car I do to make them work like they should?

1 Reply

DAVE H

MECHANIC
13,383 POSTS

Description and Operation
Parking Aid
The function of the parking aid is to provide an audible warning to the driver of the distance to obstacles near the rear bumper of the vehicle when parking or travelling at a slow speed. The system provides an assistance to the driver when parking in order to help avoid collision with obstacles.
The sensor range at the rear of the vehicle should be 1.8 meters. This should extend the full width of the rear bumper and reduce to 50 cm at the vehicle corners. The vertical range is adequate to protect the highest and lowest points of the rear of the vehicle. The system will detect curbs with heights of at least 18 cm. Obstacles, such as curbs, that are low enough to pass under the vehicle until they make contact with the tires will not be detected.
The system activates a specific speaker with a tone signifying the distance to the obstacle. The tone consists of a beep and defined space ratio which varies depending on the calculated distance. When the distance to the obstacle is less than 20 cm the speaker tone is continuous.
The parking aid is continuously in operation, unless towing when the system automatically switches off. If the reverse aid develops a fault the tone will sound continuously for three seconds when the ignition is switched on or the reverse gear is selected.
The parking aid system comprises of:
a module mounted in the battery junction box (BJB).
Four rear bumper mounted sensors which have a 90 ° angled electrical connector.
An audible speaker, mounted on the rear parcel shelf.
Diagnosis and Testing
Parking Aid
Inspection and Verification
Verify the customer concern.
Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
Electrical
ELECTRICAL VISUAL INSPECTION
Fuse(s)
Relay(s)
Wiring Harness
Electrical connector(s)
Rear parking aid sensor(s)
Rear parking aid speaker
Reversing lamp switch
Parking aid module

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
If the cause is not visually evident, verify the symptom and refer to the Jaguar approved diagnostic system.