Greetings! I have a 2001 Jaguar XK8. Occasionally, it just won't start. No Engine sounds whatsoever. I turn the ignition but all I get is a message reading "Transmission Fault...Fail Safe Engine Mode..." Also, the Air Conditioning screen reads "Err" and beeps. If I wait a while, usually up to 1/2 an hour or so. It starts! I've tried a few things to speed up the process, like putting it in neutral and rocking it a little. Or, turning the ignition repeatedly, or even leaving the ignition on for a stretch. Does anyone know what's causing this problem or how to fix it? Thanks!

 

Erratic behaviour is often a result of a weak battery - these car's are super-sensitive to battery voltage. I'd start there.

 

First thing to check is the battery. How old is it? Have you had it tested? These cars depend highly on a strong battery and exhibit many different kinds of strange issues once the battery's capacity begins to decline. Also, how often do you drive the car? If it sits for several days or weeks, the battery will slowly run down due to parasitic drain. If the battery is healthy but low, hooking up a battery tender when it's parked for several days will help keep it "topped up." You might also need to do a "hard reset" to help clear recorded issues. Search this forum for complete procedure...

 

If you are having success after moving the shifter to N, then back to P, etc., it is a sign the switches built in the shifter are not working 100% anymore. It means the computer does not know for sure where the shifter is, and gives a message. You can typically check this by making sure the light on the shifter surround follow the shifter itself. The lights are the computer's opinion (output) of where the shifter is, as per what it gathers (input) from the switches. To my knowledge, the car can start in Neutral as well, as another test. As usual, a good battery is a must, and the only true way to chase down this problem is to start by reading the diagnostic codes with a Jaguar-aware device (these will be proprietary codes). Many on this forum are more informed than me on this, but I believe these switches are generally available and a repair is feasible (but not necessarily easy as it involves adjustments). For the A/C, there is a way to press a combination of buttons to put the module in diagnostic mode and get specific codes to point you towards specific problems.

Best of luck, keep us posted.

 

 

See if this helps.

Link to A/C test and trouble codes http://jagrepair.com/images/ACCompre...or%20Codes.pdf