We just got back from a 7 day, 2015 mile road trip from Southeast Iowa to the Great Smokey Mountains. Traveling through Missouri, Kentucky, Tennessee and North Carolina. Drove the Tail of the Dragon, (what a blast), turned 100,000 miles on the way home. The car performed almost flawlessly. We only had one hiccup.
Day 1, Traveling down the Avenue of the Saints, just past Bowling Green, in the left lane cruising about 70, passing another car, I suddenly lost throttle input. The car started slowing down, pressing the gas pedal did nothing. I glanced down at the dash and saw red and yellow lights and message engine failsafe. At this point all I could do was to signal right and try to get over to the shoulder as I had almost cleared the pack of cars I was passing when this happened. I got over to the shoulder and while showing down, I saw that there were actually 3 messages. Engine failsafe mode, ABS not available, and trac not available. At first I thought the throttle cable had broke since pressing the pedal did nothing. The car was idling about 1100 rpm, so was able to move about 12mph on the shoulder. I stopped and looked under the hood for anything obvious. Other than faster than normal idle, engine sounded normal, no leaks, nothing abnormal. I shut the engine off and started trying to figure out where we were if I needed a tow truck as we were about 170 miles from home in a rural stretch of highway. Where's my code reader? Not in the glove box. I must have left it at home. About this time, my wife, who had started internet searches on engine fail safe mode, found a result that said disconnect the battery for 5 to 30 minutes to clear the code. Well, nothing to lose, but the codes that might lead to what happened. I just happened to have a 10mm wrench left in the car. So I disconnected the battery and started trying to figure out where we could get towed to and how to get the car home and resume our vacation. After about 10 minutes, I reconnected the battery, and turned the ignition on, system check, passed. Started the car, idle about 650rpm, good, no lights, no messages. Pressed the gas pedal, engine responded, good. Reset the windows and put it in drive. Yes, the car was running and moving. Hannibal is about 30 miles down the road, let's try to get there and see if it happens again. Gingerly drove the next 30 miles listening and watching for anything not normal. To my surprise and joy, the car ran perfectly. We stopped in Hannibal for lunch and decided to press on. I thought about stopping at an auto parts store to see if there were any codes, but since disconnecting the battery cleared the lights and messages and no other messages or lights came on, I figured nothing would show up. 6 days and 1800 plus miles later, we returned home with a perfectly performing car. After we got home, I took the code reader out to check the car, and as expected, there were no codes to retrieve, other than the normal p1111. The car was performing flawlessly when it happened, (as well as the last 12,000 miles) and performed flawlessly the rest of the trip.
I hope to purchase one of the pictures that was taken while we were driving the trail of the dragon and post it in the future. Have a great day.

 

Whew, that was a close one!!! Glad it worked out. BTW your wife sounds pretty cool.

John

 

I keep a 10mm wrench with my battery. It has proven to be quite handy from time to time!

 

^^ Yep, great idea....

 

Glad it worked out. Sounds like an incredible trip. Still new to XK ownership (and the car isn't really sorted out yet) so I bring a reader, tools and some spare parts on drives.

 

Same type issue with my 99. Try a hard re-set. Pull batter6 cables and tape together for about 10 minutes. Re-set your cables back on battery. Turn ignition on but do not start. Let the ECU read for parameters and settings(about 20 seconds) then turn off then turn key back on and let it sequence 10 seconds or so and then start her up. You will have to re-set radio and windows. This cleared all codes and my car now runs perfect for the last year. Best thing I have ever done!

 

I would NOT do another hard reset as the first one has worked and the car is now OK.

I'd be worried (sorry!) as to what the cause was, though. I suspect it will recur so keep the OBD tool handy.

(I'm wondering if debris on an ABS (aka speed) sensor might cause it, and may then have dropped off.)

 

I plan on making sure the code reader is in the car. I may even plug it in and monitor on the next trip, about 1000 miles next month. At this point, I want to believe it was an odd reading that may or may not be repeated. As it was, there was no notice or change in the running of the car before I lost the throttle input and the warnings came up. I have a nissan murano that I have had abs sensors give funny readings due to dirt/ debris on the highway that I noticed brief changes in power, like it was searching for traction that had not changed. But, until I can get it to repeat, so I can see what codes or what it did, I will keep on enjoying the sensational driving experience. Yes, I love the way the car drives.

 

Many of the modules keep non-current fault codes so that techs can diagnose what occurred but is now ok (typical situation when customer brings car in), so read the ABS codes if you can (and wish).

 

Congrats on the trip and the simple fix! These cars and their batteries have a unique relationship