Well, maybe.

Getting the dreaded ASC/Traction Control/Failsafe issue on my kitty (2001 kx8 convertible 73k miles). I'm working my way through what I've read here, I've replaced the battery and cleaned the wheel sensors. I've noticed something I haven't seen anyone else mention though. The first time or two it happened I was driving, stopping at an intersection, and wound up having to pull over and shut the car off and let it chill for a moment or two because of the Engine failsafe mode. No sign or warning till the lights came on.

That was last week, I replaced the battery over the weekend and it was fine for a day or two, then on Tuesday it did it twice, I cleaned the wheel sensors Tuesday night, and yesterday it still did it three times. What I've noticed though is now I can tell when it is going to happen well before I ever get an error on the dash. The revs of the engine changes, almost like it is loosing power and then surging back up to make up for it. It doesn't feel like a misfire but it is that same sort of ragged acceleration. I know then that the next time I slow down to stop I'll have errors.

Any thoughts?

 

I had a similar problem, except without the engine surge. I noticed when I stopped the car It wouldn't start until it cooled down for a few minutes. I also swapped for a new battery. One time I opended the engine bay and smelled a hint of electrical burning coming from the fusebox. I narrowed the problem down to a relay K1 and swapped it for K4. The problem hasen't reappeared since then it's been several weeks now almost a month and this issue is gone.

You might also want to check for blown fuses. I wasn't the first owner of the car but the kid that had it before me said that the car made him look too old. It had some issues but other than that it's a great car. I later found out after an overheat situation that the fuses were the wrong amps. I did a thorough swwep of all teh fuses to find that 3 of them were not correct.

 

If an xk8 makes you look old I should start taking it into the bar with me, might keep me from being carded!

I did check the 3 ABS fuses but not the rest... I'll go do that in a moment. I'll look at those relays as well, be curious to see what they do.

I spent some time this morning checking voltages, per this: http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf

All 4 sensors are well below the rating listed (1.09 vs the 2.0 to 2.2 specified) but there is zero variance between the 4, 1.09 exactly. Also no variance between taking the reading from the harness or from a removed sensor.

Also fired it up with the ABS unplugged, since I'd see some talk about doing so in one of the threads. ABS light came on for the first time ever, warnings about no ASC and low break fluid. Was running just fine so I took it down the drive way, no issues, started back, and it triggered the engine failsafe mode.

 

Me too. 2500 miles ago had trac/stab/failsafe. With advice here, I checked batt., cleaned sensors and fuses. It worked for 2500 miles. Sunday it popped up again 5 times!! Monday once on 2 mile ride. Wednesday, took it for its first brake fluid change(1999/21,000 miles), I then drove it to town to jaguar dealer (15 miles/stop and go) to check codes, figuring it would go to failsafe, and codes would be available. Didn't happen. I don't want to do anything else, until codes are read.....So, waiting for failsafe to reappear. Maybe new brake fluid helped?

 

Good call to check the fuses to see if any were the wrong size but unfortunately the only one that was wrong as a 10 in place of a 5... for the built in phone system.

At least I know I should be able to rely on my fuses to be right from here out!

 

You changed the battery and it went away for a while.

With the bit quoted above, it would seem that your electrical system goes *wonky* every once in a while. That would point at inspecting and cleaning all major connections on both the postive and negative side of your electrical system.

 

WONKY is indicative of bad connections. Dim is indicative of bad grounds and sudden outage with heat and blown fuse is indicative of + to ground shorts.

 

OK rough guideline, but those are not hard and fast rules. For example a bad ground can cause a fuse to blow due to repeated turn on surge currents form capacitors in an electronic module or from cold light bulb filaments.

 

firedog, my wheel sensors read the same as yours. My ABS module came back from rebuild today and I am not throwing any codes, so I don't think the sensors are a problem.

 

It may be your throtle body is bad. Get a code reader (e.g. Actron) and read the codes while you are experiencing the problem and with the engine running. If you get P0121, that may be the culprit.

 

Yep, those abs sensors sure seem dimmer than usual.

 

that's funny I get compliments all the time for my XK8. I could see any other Jag models but not an XK! I don't feel old in it at all.

 

Funny you say that...

Well, a week ago I did just that. I'd ordered a code reader when the check engine light first popped, a couple days before I made this thread, and it arrived the day after. By this point it was throwing into fail safe mode too fast to even clear the codes but low and behold I find two codes indicating a throttle body issue. I do a google search on the first one to find some jag specific info and get directed right back to these forums of ours. Should have searched here first it seems!

Anyways, the relevant thread involved pulling the two plugs that tie into the throttle body and cleaning them and also mentioned a SB involving the clasp of one of those plugs breaking from vibrations, creating a loose connection. I pull the plugs, clean them, and wire tie the plug with the clasp issue since, sure enough, mine was broken as well. Smooth running over the past week and no re-occurance of the issue or any check engine lights.

I posit that I had two separate issues. The first couple times I had an issue I had no lights and when I checked codes using my dad's super expensive snap on reader it came out clean. Then it threw the code, triggered the light, started cutting up before fail safe mode, etc. The first is likely the typical electric or ABS issue and may have been solved by replacing the battery or cleaning the wheel sensors or may still be waiting to pounce. The other was caused by loose/dirty throttle body connections and has now been resolved.