Engine fail safe mode

[ianfullick434]

My 1999 XK8 has the following messages on the dash readout and wont start having just been out for a trouble free run.
a) Traction control fail
b) Stability control fail
c)Gearbox fault
d) Failsafe engine mode.

Has anybody any idea what is causing this?

[mike020150]

The single most likely cause is a failing battery. Even though capable of starting a car, a battery may be sufficiently below par to cause multiple lights to illuminate. It's because the XK8's electronics are very sensitive to voltage variations. Try to borrow a new or nearly new battery to substitute yours to test against it or have a dealer do a proper battery test to confirm the diagnosis. Mike.

[Astromorg]

First question is how is your battery? If it's not in good condition it might cause those lights to appear and even if it's not the direct cause, chasing these sorts of faults with anything but a good battery will frustrate your efforts!

Just because the engine turns over smartly is not a good enough check. Broadly, if after charging fully and then leaving the battery overnight to allow the Surface Charge to dissipate, (or put headlights on full for 5 minutes plus a 10 minute wait) the battery voltage should still be greater than 12.50. If not, consider replacing it.

If the battery is OK but the fault lights persist, the next thing should be to get the fault codes read to give a definite steer to the solution.

Guesswork can be expensive and fruitless, though I would suggest checking the plug connection to the ABS/DSC module as it's a 'possible' and is easily accessible.

If you come back with any developments, the Forum may well be able to help you further if required

Edit: You clearly get up earlier than me Mike

[mike020150]

Only sometimes, John! Mike.

[ianfullick434]

Thanks for those replies I will check them out. I did retry to start the car last night and it fired up straightaway, so I parked the car in the garage and turned it off but when I tried to start it later all the faults showed again. Now this morning on turning on the ignition all appears normal although i did not try to start the car, I will later.

[mike020150]

It definitely sounds like the battery's at fault! Mike.

[ianfullick434]

It definitely sounds like the battery's at fault! Mike.

I will get it checked, thanks Ian

[BookerME]

I think the earlier responses are all on the ball.

Charge your battery up and/or test it before you start throwing money at anything.
My XKR used to give me ‘early warning’ signs of battery problems just like that – mainly brought about by me doing too many short journeys on cold mornings/evenings I suspect.
I did end replacing the battery as the old one had started to under-perform with age.
I used to joke with people about it saying there was only one thing that car used more than petrol and that was electricity!

The other tell-tail sign for me was the automatic electric window ‘parking’ that lost its setting – mine was a convertible and it had to compensate for that every time the doors were opened or closed to stop the glass fouling on the roof.

Cheers, Mac.

[ianfullick434]

Thanks for those replies, I had the battery tested and it is at 65% of its power and showed in good condition with 12.3v. I have now charged the battery and have started the car with no problems this morning. From that I do think the battery may be on the way out although it is only 4 years old .

[ianfullick434]

I thought I had it fixed but NO went out yesterday for a run about 4/5 miles stopped and turned off (in Sainsburys car park) and when I turned the ignition back on all the fault messages came back. I did call our breakdown service but after about half an hour and trying to restart without success, and then I noticed that the gear lever was not making the beeping noise when trying to pulling the lever into drive, but then it moved into drive and when pushed back into park all the messages cleared and the engine started. This leaves me to think that maybe the gear selector has a fault. Any further thoughts would be very appreciated before I take it to the local garage.

[mike020150]

Damage to the selector mechanism either through wear or attempting to move the lever without having a foot on the brake pedal is common. Some adjustment of the linear switch is possible and may be all that is necessary. This is best checked by a specialist Jaguar garage. Mike.

[ianfullick434]

My local garage has hopefully come up trumps, OBD showed ignition fault code, the relay was changed and now all seems to be good. I used the car yesterday and all was normal.

Thanks for your replies.

Ian F.