Question about ABS warning light coming on

'01 Jag XJ8 bought new, with only about 55K miles on it. When I took it in for the 40K service, everything was OK. A few days later, after a hard drive in hot weather, the ABS warning light came on. I drove a few more miles and parked. Later when i came out and restarted, no light.

This happened a couple more times, so took it to the dealer. I suspected the mechanic may have done something to cause this. This was just after the warranty ran out. They told me there was a bad brake module, and it would run about $1200 to fix it! Phooey on that. I wrote Jaguar USA pointing out that if it failed just a few miles after the warranty, it must have been defective for a while, and they should cover it. Naturally, they refused.

I’ve gone about a year since then. It only came out about 5 or 6 times during that period, and every time it did, I stopped as soon as possible, turned it off, then back on, and no light again for months. I even did this once when the traffic light just turned red. Every time it was after a fast (about 70 mph on freeway) long drive in hot weather, but obviously not every time.

I am not that concerned, as for some 40 years I drove every kind of vehicle in Vermont and upstate New York in deep snow, ice, slush and rain. If it skidded a bit, I rapidly pumped the brakes, steered into the skid, and never had a bit of trouble. As I now live in the AZ desert, not worried that in the very rare possibility that in the rain it might skid a bit, and there is never snow. And in heavy rain, I slow down to avoid hydroplaning. So, even if the ABS is not working, I don’t worry about it.

I kind of think it is a glitch in the computer or the modules reporting system, rather than the system actually being faulty. Otherwise, why would the light come on so seldom, instead of all the time?

What do y’all think?

I had a Ford that had a very similar issue - the ABS light would come on every few months when I started the car. Turning off the engine and re-starting would clear it.

I was advised to be concerned only if the light stayed on after a re-start.

The abs systems I am used to dealing with perform a diagnostic every time the vehicle is started. If it passes the diagnostic the light will not illuminate. If it illuminates while driving it has detected a fault in the system and it’s warning you of such. If you can shut the vehicle off and restart it and it does not illuminate it sounds like a sensor to me. Could be the module but only a diagnostic performed by someone qualified with the correct tools(hell only knows with a Jaguar) could tell for sure. As long as you’re driving with the light off you should be ok. In the past I seen something as mundane as an iginition switch cause these kind of problems, however.

This type of thing gets suspected a lot, but is very rare in practice.

It is a possibility, and the price doesn’t surprise me, but I’m curious as to how they reached that conclusion. Not that we’ll ever know, but I’d certainly suggest retesting and a second opinion before proceeding with that.

Possibly because some component is indeed acting up occasionally. It’s likely heat sensitive, but not bad enough to drop out consistently or frequently. I agree with Omegaman that a sensor is the prime suspect.

I am surprised to hear that Jaguar would not at least contribute to the cost of any repair.

I handled warranty for a Landrover dealership, and in the UK at least Landrover and Jaguar used the same warranty systems and procedures.
The standard warranty was three years from date of registration, but as a rule Landrover/Jaguar would cover many problems that occured in the months after the three years expired. As a general rule, driveline issues, such as a gearbox or steering rack failing, would be covered for up to an extra year. Other problems, such as an ABS module, would definately be considered up to three months after the warranty expiration date.

I had to apply via a secure web program for authorisation for these out of warranty repairs, but my experience was that Landrover/Jaguar were excellent at looking after their customers. (I also handled Ford warranties at that time, and they were the polar opposite, just a nightmare to deal with).

Jags usually have a 4 year/50,000 mile warranty. Warranties are for whichever comes first so your warranty was probably up in 2005.