My jag has multiple issues. While driving the blind spot monitoring warning, tire pressure monitoring comes on, AC shuts down and radio turns off one by one. Then it all comes back on. This repeats over and over. What could this be??
thx Randy

 

What is the voltage across the battery terminals with the ignition in the OFF position when checked with a voltmeter?

 

I’m having the same issue with my 2011 XJ Supercharged. Was driving one day and the car threw TPMS issue, blind spot issue, and the radio went silent. The A/C light will come one if I press but compressor won’t turn over. CD can be inserted into disc player but radio won’t play. The car will run fine but when OBDII reader is placed on the car, it doesn’t throw any codes. Also, if car is turned off once this occurs, the dash will stay on then eventually power itself down and it will take anywhere between 15 mins to 4 hours before the car will return to normal status to be started again. During this time, if the brake is pressed and the ignition start button is pressed, it will give a “key not found” error.

Part of me believes a motor mount snapped and a connector was damaged but between Topix, SDD diagnostics, and my aerospace engineering background, I can’t find for the life of me anything on the electrical diagram that would affect all of these systems at once.

any suggestions would be greatly appreciated

 

After spending all night going through the electrical wiring diagram, I believe the problem is the central junction box located behind the passenger seat. All of the connectors either start or end there (literally traced every connector by diagram) so I’m looking at having an electrician who works with race cars to come out and look at the vehicle (I race my XJ supercharged)... jaguar at Tyson’s corner want 740 for the junction box and another 540 to install it. Will keep you posted but if you look at the fuse box diagram that tells you which fuses connect with what, I’m sure you’ll find that this is at least where you can being. Will keep everyone posted once I finish up with the electrician....

 

If the junction box is "passive", i.e. containing no electrical components, I'd consider detaching the connectors from the box, squirting each with some electronic contact cleaner, let them have sex a few times, and see if that cures the problem, at least before spending a few $k.

 

The entire BCM and other modules are found inside of the CJB as well... Car is out to wrap (Satin Black) but will definitely try that as soon as i get it back.

 

The Jaguar certified tech asked what the battery voltage is... and neither of you bothered to reply.

Good luck!

 

my apologies.... with the vehicle off with a new battery (interstate AGM) it is at 12.6 when the car is off and 14.6 to 15.2 with the vehicle running. When an alternator clamp was added it gave a reading of .2 up to 9.4 amps still being pulled after the car is turned off.

 

Have just fixed it in my 2013 XJ - 99% you need to replace small battery in the trunk

 

CJB is not the problem source I think, coz it also was said to update software and then replace it in my case - did not help ))
I still have another CJB in garage
I asked 2 dealers in Moscow, Russia and they both couldn’t help ((

I believe user NBCat asks the right question - it is the way to figure out that the small one is not ok - can’t explain in tech word but something goes wrong inside the battery and dual battery controls module tries to save it by turning off different power consumers

 

where in the trunk is the small battery located for a 2011 X351? I’ve removed the spare tire and all the hardware that comes with it and saw nothing.

 

The "small" battery was only in the 2013 through 2015 XJs for the stop start feature. Prior to 2013 that feature was not available and from 2016 Jaguar replaced the small battery for a condenser pack to support the stop start feature.

 

My 2012 draws a constant 1.2A sitting in the garage. I would think that our two model years should produce approximately the same electrical load at rest. It's not like these cars are communicating with the factory for software updates, etc. Could you perhaps enlist a helper who could call out the VOM numbers while you temporarily remove individual fuses? It's a long shot on a "modern" car like your Jag, but this technique works on vintage cars (sometimes).

 

Our cars need a lot of electrical power, and if the battery is weak, at low RPMs the alternator may not deliver enough energy to ensure proper functioning of all modules.

I’d start by checking the battery or replacing it. How old is it?

 

battery was replaced with an Interstate AGM with 900 CCA about a month ago and issue still occurs. Today I’m going to start with swapping the Negative Battery terminal, as there is a battery monitoring system attached to it that might be malfunctioning. If that doesn’t work, I’m moving to the driver door module as whenever this happens only the driver side works and not the passenger, then radio because it comes in and out, and finally the CJB.

 

Hey Johnny, did you get this sorted? What was the problem/solution?

 

I ordered an entire new infotainment unit and then someone gave me one from the junk yard and I haven’t had an issue since... if you’d like you can private message me about the other unit

 

This issue is the result of a bad relay switch in your trunk fuse box department.

 

You know I'm glad you mentioned this,one thing I never understood, the video CD player, if you were parked somewhere and watched a, you would have one dead battery,unless you kept the car running. Anyone ever try?

 

I had the same problems, and I found out that it only occured with one special passenger on board. Everything off and on every once in a while during driving.
Also the sound of the turn signals didn't work, but the signals itself did, and when the screen was of we couldn't open the backdoors either from the inside nor outside.
We investigated more and we found out that it only happened with the bluetooth of the phone of that passenger activated.
It happend to be an interference between the bluetooth of that phone with the smartkey or the receptor of the smartkey signal.
I thought I had to reprogram the smartkey or the system, so I went to the local Jaguar dealer here in Mexico, but they told me that every Jaguar and Range Rover there had exactly the same issue with any Iphone with a configuration under 15.00.02 and that there was nothing to do about it.
Iphone's with a configuration number of 15.00.02 (maybe even from 15.00.01) and up don't cause this problem.
For several months now this person shuts off her bluetooth when she rides with us and we never had these issues anymore.
Later we found out, with another passenger with a Samsung phone, that apparently some Samsungs seem to cause the same problem.
My Huawei P 20 Pro always enters the car with the bluetooth on and it never caused any problem and connects well with the screen and everything.

This problem can also occur when you change smartkeys several times one after another.
When my car goes for service or something, I always leave the older more ugly smartkey with these other people, and use the newer one again when I get the car back. Several times using the newer key again the same problem occured. Than you have to reprogram that key again by doubleclick closing and doubleclick opening the car several times with the smartkey itself and everything works again like it should.

Something else is that for some period the smartkey was just not recognized by the car when I wanted to start it, and I had to do the following procedure if I remember well:
Press the start button once, wait some seconds, than (not before, not earlier) put the smartkey close to the dash, kneehigh at the left if your steering wheel is at the left, wait some seconds again and than press the button again.
This procedure never failed, I did it for some weeks.
But this problem has been solved right away very easily in the same meeting at the Jaguar dealer by just disconnecting both battery poles and connect them again with the same battery, not even connecting/touching one pole with another.
I read somewhere here that some people solved this problem by putting a new battery, but it seems that those new battery's hadn't even been necessary.
Just connecting again with the old one.
Driving without any problem now again for several months.
Good luck and let us know!