Good morning, gentlemen

Greetings from southwestern Ontario!

Quick question for everyone: Since I've had my 01 XJR (about 18 months), I've had a engine failsafe mode (limp mode) issue with it. Frequently, the car would kick into limp mode for seemingly no reason. Most very often only when it was cold. Between my driveway and the end of the block, it likes to kick into Limp Mode about half a dozen times - and then goes away for the rest of the day - provided it's being driven regularly.

When I started doing some investigation into potential causes of this issue, I stumbled across a few threads on this forum indicating that there was a Service Bulletin from Jag about the brake light switch and cruise control messing with each other. So I decided to do a test and drove around for a week or 10 days without my Master Cruise engaged - low and behold, problem solved! The car ran great! This naturally lead me to believe that the cause of the problem was the brake light switch mentioned in the service bulletin. So last week I ordered a replacement unit in from Jag and on Friday had it installed. Great! I thought, problem over. However, upon leaving the garage and re-engaging my master cruise, I had barely driven for 10 minutes when it kicked back into Limp Mode whilst exiting a highway off-ramp. This has left me frustrated, perplexed, and out about $200.

I noticed in the service bulletin that XJ models were also recommended to have the actual brake pedal replaced as well, but I haven't seen anyone mention that thus far on the forum. Just wondering where to go from here in terms of troubleshooting this issue.

Questions/Comments/Concerns/Criticisms?

 

What DTCs (if any) are logged in any modules???????????????

bob gauff

 

I have a similar problem, if I push to turn on cruise control switch (near the gear shifter), within 5 minutes of driving, the Engine Fail Safe Mode message comes out. If I don't have the CC switch turned on, the Engine Fail Safe Mode message never comes out. Only problem with that is I can put the car in cruise control when driving down the freeway. If someone have had this similar symptom and have solved it, please let us know how you fixed it. Thanks.

 

To the OP -- without know what codes, if any, there are it's hard to figure out what's up The symptoms that you described would lead me to believe that the brake light switch would've solved the problem, but since it didn't, I'd consider checking the installation and maybe the switch itself. I remember when I replaced my switch, the instructions are very specific about making sure it's installed correctly or it won't work. Have you considered taking it back to the mechanic who charged you $200 to see if he can get it sorted out?

BTW $200 to replace that switch is highway robbery.

To Rault -- try replacing the brake position switch, sounds to me like that could take care of the problem.