Hi all, I have scoured this forum and there is a plethora of information on Jaguar's parking sensors/ back-up sensor faults but I can't find a clear answer for the questions I have regarding mine. I have a 2007 XJR and when I put it in reverse I get the 3 second beep which means there is an error. The front sensors work but the rear ones don't. When I turn the key to position 2 and put the car in reverse, I can hear 3 of the 4 rear sensors clicking - with one giving no clicks. I bought a new sensor and replaced the faulty one and still nothing. Then I swapped the new sensor with one that was working and still nothing from that position. It seems it is a wiring issue.
What is the advice on what to do next? I am assuming that if it was a module or fuse issue that none of the sensors would click, is that right? If I should try cleaning the connectors what do you recommend I use to do so? I am hoping there are a few more troubleshooting steps before I have to remove the bumper and try to replace some wires. I also should mention I took my car to a body shop and they plugged in the scanner but weren't able to diagnose it, they mentioned some proprietary software that only the jag dealer would have access to. Does that sound familiar to anyone?

As always, any help is appreciated. Thanks, P

 

The rear bumper comes off easily. First things first. Perform a continuity test at that terminal. If no continuity you probably have a broken wire somewhere in the harness. Should be easy to track down.

If you decide to clean the connector use electrical contact cleaner and allow ample time to dry.

The good news is once you identify the issue the back up system will start working again w/o needing a reset.

 

Thanks for the reply!! Are you saying to remove the rear bumper and do a continuity test at the plug of the non-working sensor? If it is a broken wire, is replacing the wire by splicing/ soldering it to the module then running it through the trunk and attaching it to the sensor plug something a non-mechanic should be doing? Or am I mistaking what it would take to address the faulty wire? Thanks again for taking the time to reply!! -P

 

Yes, do a continuity test at the harness side of the connector. If nothing, trace the wire until you find the break. You may luck out and find a bit of corrosion in the plug. A bit of electrical contact cleaner will sort it.

If you need to fix the wire, it should be easy. No need to run new wire from the module.

 

I have a 2005 Jaguar XJ8L which had a rear parking assist fault last year, and I even positively identified the exact sensor which had failed. Actually, I still have the replacement sensor, but I don't intend to ever install it as it would cause far more trouble and expense than it would be worth. I don't know about your 2007 Jaguar XJR, but trying to remove the rear bumper of my 2005 Jaguar would likely be an extremely costly proposition. I mean, all that's holding up the rear bumper are mostly permanent plastic structures. What I eventually ended up doing was to unplug those rear parking assist sensors from the module, and then perform a hard reboot. In short, I just regarded those rear parking assist sensors as being inaccessible and hence unserviceable.

 

I'm beginning to think that's the most pragmatic way forward. Thanks for the reply. -P

 

I would not give up just yet-I find the rear sensors very useful on such a large vehicle.

You may have two faulty sensors as I have had in the past.

I suggest that you:

Remove rear bumper

Lay wiring out on the top of the rear aluminium crash bar

Fit all sensors so that they are not pointing at ground or anything that will set them off.

Ignition to pos. 2 and g'box in reverse

Replace two sensors with new and system may work

Eg replace No 1 and try replacing 2,3 and 4

Then replace no2 and try replacing 1,3 and 4

until you have tried two new sensors in all positions

Or just buy 4 new sensors