Well, not completely shut down, but a few weeks back as we were traveling home, our 2004 XJR went into what might best be described as self-preservation mode.

Major system failure message came up and the engine settled into an 800 RPM idle and transmission disengaged. Lights, accessories, etc, all working fine. Just the drivetrain was affected.

Fortunately, there was no one behind us as we approached a blind crest in the hill (not a good place to sit on a 2-lane road).

It happened at exactly he moment I pressed the cruise cancel button (ACC type) on the steering wheel, a button that has been slowly failing to operate properly on the first press.

Anyway, rolled the car back down the hill to a safe spot, turned it off, restarted and no change. Turned it off, waited about 15 seconds, cycled the ignition key three time, restarted and I've seen no problems since.

I haven't plugged in a code reader yet, but will do so shortly and let the group know what errors pop up.

Bob
Liberty MO USA

 

No codes recorded. Not at all what I expected.

 

From engineers point of view, the way safe software is written - is in a manner where unsafe input (real or from failing buttons) is treated in serious manner. In your case - the "failing button/input" may have produced input that was deemed unsafe by the software that controls engine and transmission management and it/software (the software that runs your car) attempted to shut down your car for "your safety" (just like the "patriots act" (i call it the sorry losers act that attempts to make one feel guilty for their grandfathers sins)... in any case .....

I think the following would be in order.

1. Perform a voltage check,make sure that the charging system is in good order (between 13.7 and 14.4 Volts during normal operating conditions)... Very odd things happen when the supply voltage is not in tight range. I've experienced unpredictable gear shifting when my alternator failed with a short winding (a very sudden voltage drop .... it may not be your case)

2. Make sure that there is no debris in front of the ACC (automatic cruise control) sensor

3. This may take a while to diagnose.... I would try to disengage the ACC button to make sure it's not deemed as the cause; it would be best if its input could be disconnected

4. Let me think (supply more verbal input (to the point input s.v.p. -- none of that stuff: where people get saved by the side of the road)

5. Location: Liberty (it better by as in Ron Pual Liberty)