'99 XK-8

Sitting at a traffic light, I stepped on the gas and the dashboard lit up like a Las Vegas slot machine:
1. Stability control failure and
2. Engine in failsafe mode.

Nothing noticeable was happening when this happened and when I limped to the shop, the mechanic checked the codes (which I didn't get) and said he'd never seen such a thing. He erased the codes and the car runs fine.

Any clues?

 

I've moved your post from the General Tech section to the XK8/R section where it will get greater visibility and better response.


It could have been a number of issues but without codes it is hard to even guess at this point.


One thing to look at - the electronics in these cars are sensitive to a weak battery. How old is yours? Take it to Advance Auto or Autozone and have them check battery and charging system for starters.

 

I second a weak battery as the culprit as it happened at idle when the alternator output was lower.


Dave

 

The battery is about 1 year old. Admittedly during the summer I don't drive the car much, but I try to get it out at least once a week. The voltage gage normally stays straight up, but I'll watch it more closely.

I also bought a code reader/killer as this seems to be a useful tool to carry about in your Jag.

Winter is when the car gets driven when it becomes too cold for the motorcycle.

 

Bad Battery or ground in trunk, the one that runs from the battery to the trunk.

A bad ground will kill a good battery as it arcs slowly while the car is parked or driving destroying the cells inside.

So can the positive cable in trunk and corrosion on the mega fuses on the positive cable in trunk, and a bad tranny ground strap up front.

If it does it again, let jaguar look at it. They only charge a hour or 2 labor and figures out 99% of all issues with that charge

 

Did it stall ?

 

No, the car never stalled or missed a beat.

This last weekend the stability control fail signal came up again but without the engine problems. The car drove fine going home and I shut it off in the driveway. When I came back out 5 minutes later and plugged in the code reader, there were no codes showing. When I started the engine, there were still no warnings.

It's been a week now and nothing. No news is good news. The roads are now slick and I can report that the ASC seems to work fine.

 

I have to agree with the others that this sounds like a battery issue and I have experienced infant failures in batteries before. Just a year ago the battery in my X-Type failed after less than a year and AutoZone replaced it for free under the warranty.

 

Does your reader see jaguar ABS codes? Most do not.

 

I asked about the engine stalling because my '99 XK8 did exactly the same thing as I was accelerating AND turning to leave a wash & vac business in town. I wasn't trying to 'burn rubber' but I was being slightly aggressive as I was circling the lot and all of a sudden (I hadn't gone more than 10-15 feet) the dash lit up like yours and the engine died. Turned the key off and then immediately restarted without further problems. Same thing, no codes.

 

As others have stated, the battery is always the first component to suspect when mysterious electrical gremlins begin to appear and disappear. These cars draw massive amounts of power and when the battery begins to dwindle even just a small amount, strange and unpredictable things pop up. So check that battery....

 

Did you run the car through a automated carwash? That has caused electrical problems for several members.

 

No, just one of the ones where you do the work. In my case I think it was the sudden acceleration coupled with a lot of steering lock as I was making a U-turn in their parking lot. Even the best computer controls and modules can occasionally be caught napping.<G><G>

 

I say throttle body. Can you get the codes from the guy that cleared them?

Gus
www.jagrepair.com

 

+1 - that's my bet as well. As Gus said, get the codes or else it's guesswork.

 

Chilipepper 2002 xkr did the exact thing + stall on freeway for the second time in one month.
Of note: car spent the night with lights on. Quit after 10 min of highway driving at night with A/C on.
Battery is from 2012.

 

OK it's back after 4 months of regular driving. ASC failure, Engine in failsafe mode, AND ABS light.

Elsewhere on the forum it is suggested that the ABS module has a couple of solder joints that fail possibly because of being next to the pump connection which develops a poor connection and gets hot. That said, the consensus is that removing the module and re-soldering the connections takes less than an hour which would be nice if it wasn't February in my driveway.

All in all the car is nice but I've had Brit cars from the 60's and 70's that ran more reliably.

 

O.K. this seems to be the fix:
https://www.jaguarforums.com/forum/x...-repair-62539/

Includes step-by-step instructions, pictures, and a tool list. dsetter says this should only take an hour or so but he has a sedan which is easier to get the offending module out of. Echoharper says it's not that hard to extract the ABS module from an XK8 but looking at mine I'd say it's not going to be real easy in any case.

Here's another approach with helpful pictures:
JagRepair.com - Jaguar Repair Information Resource

This looks like it involves less can opener work although I'd say be VERY careful with that hole saw. There seems to be about 3/8" of clearance though and the removable plug will make it easy if you have to do this again.

The funkey little screws holding the module to the manifold require a Torx E-5 socket from NAPA for about $3.

 

You can get the ABS control box out without disturbing the hydraulic connections but it involves bending and twisting the brake lines. When I did mine I tried that first but then decided it was safer to disconnect the lines and use the opportunity to flush the brake fluid at the same time. Harbor Freight do a vacuum one man brake fluid changer for $39 which makes the job very easy. Brake fluid should be changed every two years or so anyway so to me it made good sense. AFAIK however, an ABS fault won't trigger limp home mode, my bet is still the throttle body but you need to pull the codes.

 

When the ASC kicks in the engine is automatically reduced from 8 cyl to 2 or 3 or something like that. If the Stability control is stuck on, then the engine would be permanently in limp mode.

I'll fix the ABS module and see if that does it.