Blind spot, back up camera not working, low tire warning, etc. misc intermittent electronics issues

 

Unexplicable sudden errors usually means the battery is near its end of life. The last gen XJ draws horrendous amounts of current due to very many distributed computers within the car. These modules start to act up, when the battery is weak. Changing the battery is one of the cheapest repairs you can have with this car.

A quality AGM battery is recommended.

 

dddesbien, like was said by NielsL, odds are, your problems stem from a weak battery. Going with a quality AGM battery is what the car needs. Will a standard battery work in the car, kinda. Yes, there are differences between an AGM and standard battery. This is why going with an AGM battery is needed. In short, the AGM battery is capable of handling more small discharges and can pump out more current when asked over and over without hurting the battery. If after the battery you are still having issues, please let us know and we can get you back to 100% through some simple checks.

I know some people are going to argue me on this. When changing the battery, let the car go completely dead. This is going to force the computer to learn your new battery. With this being said, you will need to also reprogram your sunroof, sun shades, window one touch feature for each window, and the e-brake. Not a big deal. Takes a total of 10 minutes to do. Keeping the power in the car with an external source keeps what the computer knows about the battery and it can lead to minor overcharging of the new battery. Over time the computer will learn about the new battery. If you have the battery done at a dealership, they will tell the computer to learn the new battery with their dealership level diagnostic equipment.

 

I have these issues and they didn't go away with a new battery. I was working through the electrical diagrams and everything throwing a fault goes through the lower left connector on the junction box behind the center of the rear seat. The arrival of a new baby kinda stopped me investigating further as it doesn't affect the performance at all.but it's on the back burner for now. My next step was going to try and re-seat the connector and check for a bad ground or a short.

 

I haven't noticed the faults yet, but I have noticed that if I leave the lights in 'auto' mode, the drl/ parking lights will not turn off and then a little later, the horn/ alarm will blow and show 'bonnet' open warning and I can't lock the damn car. When I switch the lights to full off, I guess the battery charges with driving and when I go to park it at end of day, or at work, as long as I leave lights switched to off, I don't get the alarm going off and bonnet issue.
Oh and the steering column won't adjust and my usb ports don't work in the arm rest compartment. lol

 

The light switches often fail at some point in time. Mostly the fault shows by flickering headlights. But if your problem diappears by switching the light off, it indicates a problem with that switch. Just unscrew the 2 bolts of the steering column shroud, and you can separate the shroud without taking off the steering wheel. Have a look at the cabling and check correct seating of the connectors. Gives you access to that steering column adjuster joystick too.

 

Thanks for the info, I will definitely take a look before ordering shelling out the cash for another.