Marshall, first off, welcome to the forums. There's a lot of people around here that can help you out and I'm sure with a little bit of assistance from us, you can figure out this issue. But, we do ask something from you first though. Please stop by the "New Member" section and introduce yourself. We are a friendly bunch and like to get to know each other. This is one of the things that makes this forum different than most. I think you will also figure out who the movers and shakers are around here.

As for your problem. I would recommend doing a look at the wiring harness that runs along the driver's side of your car near the throttlebody. It is possible that it has been damaged and it is making periodic contact with the body, grounding out the signals needed by the tranny computer. This will then put the tranny computer into a "protection mode", leading to the things you are seeing. Lets start there and then we'll get into other things and see if we can't get this taken care of for you.

 

Sidewalkman: have you seen my post about the TCM? My car was doing just what yours was. I always thought it was when it was raining but then it started doing it all the time. Check the TCM, its worth a shot!

 

Dude, search out threads that I have started, I am the king of all things TCM, it'll be water and moisture damage to yours. It's beghind the fuse box under your dash, it is a complete puke to get out. Take it out, dry if off (you won't think it's wet) take the cover off and you'll see where the moisture has attacked it. Clean all the connections and pray it hasn't shorted. Next figure where the water is coming in, you can read my first thread about it. Then hang it out of harms way by the harness up further with zap straps.

 

OK, just to close this off. Last weekend I put in a new battery, when I pulled the old one out I checked all the connections and the cables, I didn't think there was an issue as they never really were really heated so no short. Sure enough everything was fine, no bare spots, no rubbing, all connections good.

I put the new battery in and she's been good ever since. I was sitting in a border line up yesterday and no issues. So looks like the battery was the issue all along.

 

I had a ford 500 and the power mirror would move all by it self, rain and humid days, found the problem, a hairline crack, in the door/a-pilar connector that washer fluid had leaked into, and on high humidity and rain drew moisture, and short central. you mentioned you had fluid on a connector, pull apart and see if discolored, may be part of the problem, shorting out with heat and or moisture

 

Well, it was a seven year old battery. Some can go to ten, but not very often.

 

So I'm driving home the other day. Guess what happened.....the same thing. Apparently the battery was not the answer.

So I'm back at square one. starts with a shudder, then gearbox fault, followed immediately by the DCS system fault and lastly engine system failure. Terminals and wires are warm but not hot on the battery, no CEL or codes. I shut off the motor for 30 seconds and I'm good to go, for how long who knows because the condition gets worse over time. Odd thing is it was happening 5 times a day before I replaced the battery, up from once a week or 2 when it started. Has to be electrical, doubt it's the computer since it doesn't store a code, I'm still thinking a bad connection someplace. And because it's so intermittent it's a connection that controls everything that somehow disconnects momentarily.

I'm wide open to ideas.

 

sidewalkman,
I drive Buses for a living and they have so much computer operated gizmo's and what you experienced is something i get on a daily basis, Technology tripping over itself lol
Default cure is turn off, isolate, wait 10 sec's restart everything has reset. My thoughts are microsoft must have a share in auto electronics.
But i am assured they dont have any in the space program apparently

 

No codes? It would be weird if it was electrical and not giving codes... do you say "no codes" because the check engine light is not on, or have you tried to pull them anyways?

 

I carry a code reader in the glove box...seriously I actually do. I have in another thread what might be the outcome. It got so bad that even with the engine off if I slammed the brake pedal down while in the run position it would pop the DCS and Gearbox faults. I finally googled all the faults together and apparently although not really common on this forum the XJ guys have had it forever, but they include something to do with the e brake. All rolls back to the TPS on the throttle body.

Most people said don't take the TB apart or mess with it but I figured if mine is pooched already what harm could I do. I got a can of TB cleaner, pulled the thing off, pulled everything that could come off, off, then sprayed and cleaned everything I could. It was pretty filthy, like a reaction to using regular fuel, so for the people out there using the cheap stuff, learn from my mistake and use at a minimum mid grade.

In any case after I put it all back together and double checked for any vacuum leaks it ran good and didn't return any faults when I slammed the brake pedal down or anything. I honestly haven't been driving it though. I'll be back to driving it daily again now so we'll see. I don't have as much faith as I used to.

 

I had the this happen top me today for the first time. Sidewalkman, Did you ever figure out what the issue was? I was pulling off the interstate and as soon as I turned the cruise off it went into "limp" mode. Yurned the car off waited 30 seconds and now its fine. only codes thrown are P0420 and P1111. Any help would be great!

 

Odd, you got codes, I never did but from the look of it you have a vacuum leak. Open the hood, the tube going back on the right from the intake or the tube off the brake boost might be cracked, you should be able to hear a hiss, easy fix with duct tape until you order the replacement, they're cheap too.

 

Thanks for the advice. I will check it out today and update if I have any results.

 

So I thought I's end the thread with the results.

I've been driving it for a month or more since pulling apart the TB and cleaning it. No issues at all.

Back to the same old car it used to be.