So I had all three come on for a few minutes on my drive home from Birmingham. My friends were playing with the S button and the Tach button (I honestly don't know the names for these. I think one is for the sport suspension. Anyways, as I was braking, they were pushing them a few times and when I came to a complete stop the lights came on.

About 50 miles down the road I parked it to get gas and when I turned it back on the lights stayed off. Throughout the rest of the trip everything seemed ok, but I didn't hit those buttons again.

Could them pushing the buttons so much in a short period of time have caused some screwy electrical issue? Or is this something deeper I need to look into.

If so, where should I begin? I've read that it's a semi-common TPS or sensor cable issue or even something as minor as the Wheel speed sensor being cleaned.


I feel like I need to buy a second jag. One to drive while I fix the other.

 

Those are the Sport Mode button and the Cruise Control button. I doubt they would have anything to do with the ABS/TRAC/ASC lights. Those lights are related and it seems like if you get one, you get them all. Mine come on once in a while, maybe after going over a bump or jarring the car and stay on until the next time I start it. My Land Rover does the same thing. It may be a wheel sensor doing a hiccup. I wouldn't worry about it unless it starts happening frequently or the lights don't go away. Of course it doesn't hurt to clean the wheel speed sensors.

 

Ditto what Jim said. My ABS/Trac/ASC lights came on right after I wired up a direct input to my CD changer, so like you I thought it was an electrical glitch. In my case the lights eventually stayed on so I had my mechanic check the codes with a reader that can read ABS codes and it revealed the module was the problem. It can also be caused by the wheel sensors getting dirty.

A bad module is a common DIY repair you can learn about on this forum or you can pull the module and send it to someone like Module Masters and for a $100 or so they'll fix and return. They also have the procedures online for pulling modules and checking the sensors. My mechanic wanted $350 to do the whole job.

If your lights stay off it may just been a dirty wheel sensor...

 

reading about a passenger who repeatedly hits switches, my god, it makes me want to slap them, are they special needs or children? why would someone want to do that?
The sports button enables a higher shift point, so it alters the gearbox map. If your car has CATS active suspension, it also engages the firm setting to each shock absorber.
The cruise control system on your car may not have appreciated being enabled/disabled rapidly, as it attempts to set a speed, then that is cancelled and set over and over.
ABS/TRAC/ASC warnings can be put down to the already stated dirty wheel speed sensor, faulty solder points within the module, or weak/failing battery and charging system, plenty of reading to go at there, but I wouldn't have those friends touch a thing next time.
Analogy time - I once went out with a girl that ordered food, then decided on something else, by the end of the evening the waiter, chef and myself were in a state of anxiety, I think your friends might have given the XJR the same feeling.......

 

Going to work on my Wife's Pontiac today. Going to try and throw the jag on the lift too and clean the sensors.

 

Any warning message on the instruments when starting the car? It can be the "Trac off" button pressed? If you have the radio's code, you can try a hard reset, taking off the negative lead of your battery,touching the positive with it and leaving for 15-20 minutes.