The dreaded limp home mode...again
 

I do realize that this has been addressed over and over, but unfortunately it is not one of those things that resolves in a straight forward manner, like "Oh, this is it, this one thing will take care of this; we're done". No, unfortunately nope.

For a while by now I have been living with the infamous XJR engine problems that throw the system into “limp home” mode out of the clear sky. This has repeated several times during the last year, or so. It may go fine for a week or two and then, when I’m beginning to trust it (and drive farther away…) it again fails and in spite of all the work and expense it has generated. So, the car just sits there while the others cars get the drive (the XJS and the Z3). I basically can no longer trust it for anything longer than just a few miles, otherwise I’m facing the dreaded limp home mode for miles.
· ASCnot available
· Tracknot available
· Failsafe engine mode
... and more
Below is a summary of what has been done in regards to this problem:
ITEM ITEM STATUS
· ABSModule ………………………………….Rebuilt by British Eurotech
· Throttlebody Assembly …………………….Replaced by British Eurotech
· EngineECU (Used) .…………………….….Replaced by British Eurotech
· Brake switch ………………………..………Replaced by British Eurotech
· Wheelspeed sensor(s) …………………….Cleaned and inspected all four sensors by owner, in spring of 2014
· Borderline low battery charge ……………..Fully aware of this issue, the owner keeps the battery fully charged 24/7

Also, I’m sure that the shop is aware of all the potentially suspect power wiring connections and, after all this work, the shop must’ve included some serious inspection.

The hard reality is that, by now, this carries a nasty cost in receipts, yet I still cannot trust the car. The question is, looking at above list of what has already been spent on, what else is there to replace (i.e. spend money on), other than changing again what’s already been changed? I’m not looking forward to shelling out more of this kind of money. Jeez, just the other day I responded to one of those offers for “Extended Warranty on a used car”, but when I revealed that the car in question happened to be an XJR they said “we don’t cover XJR’s”...hmm, I wonder why.

So, it’s only obvious that the idea of getting rid of the car is growing in popularity yet, I otherwise love this car and totally wish that I could say “this problem is now a thing of the past”. Thing is, if I sold it, what am I going to tell the new owner, and, if I do say something, is the car going to sell at all? and if it does, will I get more than $3,000.00 for it? (Jeez, just the ICE alone in this car is worth much more than that, see gallery).
I realize that there’s plenty of Forum writing on this subject. I only want to know if anybody here may have a different angle on this overall picture, be it the failure issue itself, or the disposal of the car issue, etc.
Many thanks in advance.

Cheers,

Every time I have ACS and TRAC not available the first thing I do is get a new battery. You need to solve the low battery problem, that causes all kinds of gremlins. Once you solve low battery clear the codes take it for a ride and if it acts up read the codes and lets move forward.

As to selling, sight unseen I'm in for $3,500.00 lol. And I'll fly in and drive it back to Omaha.

Forcedair:

You did not mention if you have a MIL light or if there any stored codes!

Use this diagnostic sheet to test the wiring to the wheel sensors.
http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf While the car is in fail safe mode check the resistance of the front wheel sensors at the ABS unit.


The cables connecting the front wheel sensors to the chassis wiring would be my 1st guess. The usually break right at the wheel sensor connector. On my car it was the front passenger side cable.

Yes, trouble codes ? Battery, and connections. I wouldn't assume about the power and ground connections, battery, battery.

Actually, the low battery problem should be already resolved. Ever since the first time I heard of the importance of battery charge in regards to this problem (about 1 1/2 years ago) I, first, purchased a new battery and, second, have kept the battery fully charged at all times.

In addition, I have gathered a few related devices to stay ahead of the (electrical) game. I keep a digital DC voltmeter in the cigar lighter receptacle 24/7 which I can assess based on my own experience with battery idle voltage and/or alternator charge voltage, etc. I do not let the gauge reach 12 volts, let alone below that and if it does reach 12v or below it's re-charging time. I also have gathered a bunch of the latest charger/maintainer equipment to help me with the other cars, as well (clearly, I'm not driving a lot).

The codes that I remember were C1095 and P1632 and the work that the shop performed were based on those codes, including the rebuilding of the ABS unit. I still need to find where I wrote down the latest codes that I gathered with my OBDII reader.

It's like I said in the opening post that, unfortunately, this XJR problem is not one of those things that can be resolved in one straight forward manner, like for instance, the timing chain tensioner, where you either do the job yourself, or pay to get it done and, even if you pay dearly to get it done, it's done and your problem is gone forever. I have spent over $3,000.00 on this problem, yet my wife won't even take the XJR to the grocery store a few blocks from home.

Not too long ago, your $3,500.00 offer would have sounded like a funny line, but after all this gloomy picture it may be a reasonable one, after all. You see, if somebody came and told me "Reinaldo, for $1,500 I'll fix the problem for you and with a generous warranty" I would take the offer.

I just need to trace some lines here and I'll be making some decisions, including your offer. Thank you.

Cheers,

C1095 and P1632 were the codes that the shop worked with, including the ABS rebuild. I need to find where I wrote the latest codes, either that or I can wait for a new failure and read them with my OBDII reader.

Cheers,

Thank you, Rockland. Yes, that's a great diagram to have for this purpose and I actually used it a few months ago when I thoroughly cleaned and inspected all of the wheel sensors and wiring/connections, including for specified resistances and wiring integrity (i.e. wiggling) from point to point. That time I didn't find any discrepancies and the job didn't necessarily resolve any problem, but it was nice to confirm that everything was clean and well connected. I may repeat this job the next time we limp home...

Cheers,

Way back, Danielsand had the same problem -- if my memory is correct -- it was a wire to the wheel sensor and he would get the message after turning left out of his driveway. Fixed the wire, and that problem was solved . . .

i went over a rough bump and my xj8 started going into limp home mode ever since after about two minutes of driving so in my mind something was jarred loose or broke and that's causing it and its probably the wheel sensors/wires. so far I've cleaned the MAF sensor to no avail. i didn;t see a MAF sensor clean or replacement on your initial list of things you've done, that's why I'm mentioning it.

That's a good point, but I would've thought that when the shop did the throttle body they should've cleaned the MAF sensor, too, since it's right next to it. In fact, that's what I did myself back a few years ago. I cleaned the throttle body and that included that procedure to cleaning the MAF sensor along with it.

In fact, if I remember well, I think that was the only time that work related to erratic engine that I did myself actually resolved the issue at hand. It was that issue when the engine goes erratic just a couple of blocks away from home because the throttle butterfly sticks to the bore and the fix is to clean all that black goop from the bore surface.

Jim, would you know, or remember if there were any codes and/or which codes were they?

Thank you, cheers,

limp home
 

From what I have read on this forum, the symptoms you describe; ASC not available, TRAC not available, failsafe engine, when occurring together, indicate a voltage problem, usually attributed to the battery. You seem to have eliminated that by keeping it charged, and monitoring the voltage. Have you taken apart and cleaned all the cable connections from the battery to the front of the car. There are also several component earth connections that can corrode, also the main earth lead from the motor to the chassis. A bluetooth OBD connector used with a program like Torque on your smartphone will enable you to monitor fault codes.
good luck

I have attached a great electrical troubleshooting guide one of the forum members put together. Grounds and cable connections may appear good but it is what inside that creates the problems.

"Jim, would you know, or remember if there were any codes and/or which codes were they?"

Reinaldo: Do a search against Danielsand's contribution (fairly large, heavy on timing chains) and you should find that particular thread response. I don't remember if he had codes and he wasn't one to head for a dealer to use their complement of software.

Did you resolve this?
Have you also checked the engine to chassis ground strap that causes charging and voltage fluctuations?

My limp home prob in my 1999 V8 Sovereign was diagnosed and fixed by Peter Godwin as deteriorated solder connections in the ABS control unit.
Then there was the throttle body...
All fixed a couple of years ago!

Limp Home Madness
 

I had a similar intermittent problem with my 2K XJ8 but it would only start "limping" when I pushed the accelerator down to the floor. It would also hesitate sometimes during gentle acceleration as well. I followed the advice from one of the posts here and cleaned the connector to the TB with contact cleaner. All good for now but I'm keeping in mind that the vehicle is nearly 18 years old so dirty connectors (and there's lots of connectors) may be a recurring issue. Contact cleaner is now part of the things I have stowed away in the trunk.

Good luck!

Well, first I want to say that just the mere mention of the word "accelerator" is a highly telling clue. A few months ago I was getting the limp mode to intolerable levels, but as soon as I started to include the word "accelerator" and/or "pedal travel" on my reports to Nigel at Eurotech (now South Bay British) he immediately suggested that I needed a new throttle body assy. He also warned me about how the exchange "reconditioned" units out there are very low percent success because there's no such a thing as serious and successful repairs for these units and that he would only install it for me if I purchased it. Well, guess what, he was right and the exchange ASI throttle body assy didn't work, so I took my car to Mitchell's British Automotive in Culver City to see if they could do some miracle with it. They were also well aware of the situation with reconditioned units and also suggested that a brand new unit was the only answer considering the car's age and miles and that everything else, as in cleaning this and doing that was a total waste of time and money, only buying some short delaying of the inevitable at best. I had to bite the bullet and I purchased a brand new factory throttle body from the Santa Monica Jag dealer and after $3,000.00 the problem totally went away and it has never come back, not even a sign of hesitation, what a relief, finally. This would've been the solution from day one, had I been timely and properly advised. This car is a phenomenal machine and $3K after 90,000 miles is nothing if it is again back, happy and working as it should.

Actually, I still have the ASC warning coming on, probably from dirty wheel sensors that I need to clean again, but which is a totally different issue from the throttle body. However, you can just imagine how this was a highly confusing warning back when the car was stalling and going into limp home mode because of a totally different (and then unknown) reason. Aahh, but the car is so beautiful and sooo worth it....

That looks good i wonder how far off it is from the oem speed pack spoiler also are you equipped with the mins gallery dual exhaust?