Electrical problem XJ8 vandan Plas
This Electrical problem has got much worse and cannot find a cure yet. HAve been having the following fault show up on dash for along period of time --ABS symbol always showing together with Traction and Stability control failures-flashing on the dash. This has not stopped us driving the car . In October last year my wife was driving the car and it suddenly slowed down and dash showed Transmission fault -Fail Safe engine mode--engine would only idle. Had car taken to local Jaguar mechanic who could not find a problem and reset the error codes and car appeared to be okay for a couple of weeks. Initially when we got the car back from mechanic -dash showed no errors- but after a couple trips out the ABS symbol came back on dash together with the Traction and Stability control failure flashing. Car still drove okay--then just before Christmas the Transmission Fault appeared with Fail Safe Engine mode, Not sure what to do now to correct this problem ?
Also we know there is nothing wrong mechanically with the engine and transmission.
Also we know there is nothing wrong mechanically with the engine and transmission.
+1 Gus,
It is uncanny how often a battery that is about to go over the cliff starts throwing up this broadly similar grouping of faults. Not an exclusive cause, but always the first and logical place to start.
Regards,
Ken
It is uncanny how often a battery that is about to go over the cliff starts throwing up this broadly similar grouping of faults. Not an exclusive cause, but always the first and logical place to start.
Regards,
Ken
I replaced the Battery about 18 months ago, will check it --but I am wondering now if its corroded terminals on the negative to chassis. I believe you should always disconnect battery with negative first/
If you imagine not doing this but instead starting with the other terminal and accidentally shorting terminal to body with a spanner, you're risking a serious incident as HUGE currents flow. Not worth the risk.
OK, so in case you do have a bad power or ground connection then clean them up, reconnect and after that smear with vaseline (petroleum jelly). That's an attempt to keep moisture out so all stays good.
Although I don't recall Positive lead being reported as an issue on X308 (and I never had any problems with mine), this is a known fault on X-Type and XK8.

(click on the image to enlarge it)
The Positive lead loosens or the terminal corrodes in the HP protection Module (item 5) giving rise to spurious faults even with a healthy battery.
Worth checking and eliminating on your X308 ........
Graham
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Well...getting BigDaddy back from the shop tomorrow. Didn't have a bad alternator after all. Just a dead battery. Got the steering colum tilt/telescope feature fixed. They said it had been looked at previously and got put back together wrong. Pinched wires. But holy regaling frak....they charged me $460 for that plus another $100 for the battery. How hard can it be to wrap wires properly?
I doubt your ABS issues have anything to do with your tranny problem.
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99xk8guy
XK8 / XKR ( X100 )
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Sep 29, 2025 10:51 PM
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