I was driving my 2003 XJR at 70 MPH and Fail Safe Engine Mode, Restriced Performance, ASC Not Available, and Trac Not Available all popped up. I had no acceleration and slowly slowed down and parked on the side of the freeway. I put it in park and turn the engine off. I restarted the engine and it drove normally full performance. I took it to the Jaguar service place. All they got were codes B121 and P1632. They replaced the throttle control relay, cleaned the throttle body, and checked how tight the throttle body’s cable was. I am hoping the throttle body doesn’t need to be rebuilt. This throttle body is a rebuilt one from ASI that I got 9 months ago. Their warranty is only 6 months.

 

If it happens again check if the brake lights are constantly illuminated, I have this problem and I believe it is the micro switch for the cruise control on the brake pedal.

 

This may help you better understand the reason for your TB and condition, its actually done by ASI... ...they even give their number to phone them. Being yours was already done by them, and if they are honorable, they should give you a couple things to try to alleviate the issue.
If not, be sure to post here so others will know whether to use them or not. But don't be negative if you haven't thoroughly done what they said. We don't want to tarnish someone's business for illegitimate reasons. But give kudos where deserved also.

 

It happened again today.


P0121 Throttle/Pedal Position Sensor A Circuit Range Performance.



Fail Safe Engine Mode, ASC Not Available, and Trac Not Available all popped up.



Am I going to need ANOTHER rebuilt Throttle Body?

 

Have you contacted ASI?...I revert back to post #3.

 

I watched the video and erased the codes by touching the battery wires. So far so good. I need it to make it to work today and then the Jaguar service place tomorrow.

 

 

 

Ok, sounds like the reset is holding...don't be afraid to contact ASI and ask them about it even though its not sending any codes. I'm quite sure they would give you some other things to check just to CYA. This way if it does send another code, you'll be prepared with a check list and/or whom to contact there for assistance.

 

I called ASI. Their advice was maybe it was the harness. They also said clean the connection to the pedal position sensor. The Jaguar service place mentioned replacing the connection. ASI said if the same error message happens again send the pedal position sensor in and they can fix it. Over 200 miles since the error message and the Fail Safe Engine mode happened and it has not come back on.

 

I have a 2002 XJ8 and 2 weeks ago I had this happen 2 days in a row... never while I was driving, but after I had been driving and parked the car. Day one was at a store. I went shopping and went to start the car again and it would turn over but not catch. On the dash flashed "Fail Safe Engine Mode, ASC Not Available, and Trac Not Available". Someone came and jumped the batter and it started (even though the battery had not run down. The next day, I had the battery tested and fully charged. Then I took it by a jaguar mechanic who said they couldn't look at it for at least 5 days. I needed to work so I drove the car anyway. That afternoon... the same thing happened again. same messages on dash. A friend jumped the car. I took it to the mechanic and they got it in 3 days later. They tested everything and took it through paces. They said they couldn't get the car to fail or duplicate anything and no codes came. It's now been 2 weeks and I'm driving it, and it hasn't happened again. But I still don't know why it did that. I did buy an all in one cable and battery jumper that I'm keeping in the trunk in case it happens again and no one is around who can jump me.

 

Hi I am not sure I understand what this is. I just posted about my car not starting twice with Fail safe etc. messages. Today I had someone tell me one of my brake lights is out. Could they be related? I'm also finding myself constantly turning off the cruise control button that seems to go on without me having pressed it (in the center console). Maybe it is on automatically when the car starts. Cruise control its self isn't engaged (unless I do it deliberately from the steering column when driving), but the button in the middle is. Just wondering if there is something i can do since the mechanic couldn't find anything wrong. Thank you.

 

Are all your brake lights out? Your issue appears different than the OP's scenario albeit you found a answer similar to your issue. First off I would recommend reviewing this thread for the brake lights... https://www.jaguarforums.com/forum/x...orking-193530/
...you also may simply have a faulty brake micro switch down on the pedal (posts #5 & #6)... https://www.jaguarforums.com/forum/x...rn-off-202602/

...for the no start condition, I am suspect it may simply be a dirty CPS (crank positioning sensor), see Vern's #4 response... https://www.jaguarforums.com/forum/x...-start-202411/ ...the other possibility may be a failing fuel pump? But we'll only get into that once you review the other stuff.

I don't doubt there is the possibility you have a single source issue for multiple problems, as Robman25 posts, but lets check the more common single issue problems for each area also. The combination of issues may be a coincidence.

 

Hi Thanks for the response. Ironically, last night I was driving home and up popped ASC Not Available, Trac not available and the ABS light illuminated - which had not illuminated before when the car didn't start. What did not happen was fail safe mode and the car didn't lose power and I was able to drive it home. (I was very nervous though because it was on the highway). Also, this was after a major rainstorm, so maybe that affected the ABS? I don't tinker with cars, and I'm not sure what to tell the mechanic because they couldn't find anything before, and it cost me money for them to look at it and say nothing. I'd like to be specific with suggestions when I speak to another mechanic. I'm looking for another mechanic who works on Jags who might be able to figure it out. Thank you,

Also, not all brake lights are out, just the right side, so I'm hoping its only the bulb.

 

You can do some screen shots and show the Tech what you've been shown. I've given you the post #'s to look at.

Go to the Regional forum... https://www.jaguarforums.com/forum/regional-34/ ...and ask someone there if they can recommend an Inde' (Independent) which should save some money. Being in Colorado, and where?, you may be pressed to find one. I've been over most of it (Durango to Steamboat Springs and over to Denver to Trinidad) It also sounds like you may have a ABS module repair to do. Now that can cause a couple of codes but be one issue. The repair procedures are here... JagRepair.com - Jaguar Repair Information Resource ...be sure to use the Home prompt for that site and bookmark it for future use, its a good site done by a member here. You can also send your ABS out to be repaired if your not comfortable doing it.