Disconnected battery on a 1999 jaguar xj8. re-connected 5 days later and thought the battery was dead, battery is reading 12.75 v but there is no lights on the dash just error codes reading failsafe engine fault, gearbox fault and electrical fault. The car had difficulty in locking and unlocking with key fob prior to this. is it immobiliesd, can it be fixed?

SOURCE: engine light flashing

The most common problem for a misfire and a flashing check engine light is the ignition coi on plug.
Each spark plug has its own coil pack. With a coil pack failing it will also cause a airflow code as the car will start to run rich. With the vehicle misfiring it can also inhibit the Cruise control but it will not necessarily bring on a gearbox fault. The most common cause of the gearbox fault light coming on as you describe is usually a weak battery.
I would replace the coil pack and have the battery tested.
Thanks and good luck
JPTCAT

SOURCE: x-type jaguar automatic (gear box fault)

remove the positive battery cabelf ro 10 mins to reset the computer....

John Quinn

• 286 Answers
• Posted on Feb 17, 2009

SOURCE: x-type jaguar automatic (gear box fault)

Hi

Get a jump start, with a good set of leads.

Connecting + to + Positive to Positive..

Negative to Negative --- to ----, and have your battery tested.

Expect your battery is shot !

Good luck !

John.

A FixYa rating would be Nice....Thank´s ..

SOURCE: GEARBOX FAULT MESSAGE for jaguar s 2001

Replace transmission and sell quickly. I bought 2001 s-type in October 2008. I have not been able to drive it. 1st thing was gearbox fault message which turned out to be transmission. Ford can rebuild cheaper. Next thing to happen was all seals needed replacing. Then all coils needed to be replaced. Coils keep going out. Needs new computer which has 8 year/80000 mile warranty on, but Jag would not honor ($3000). Needless to say my pretty jag sits in the driveway. Had to get another car. Went with Lincoln LS V8. GREAT car!

SOURCE: Gearbox fault of Jaguar S Type

unfortunately when that code, and that gear box fault light comes on, its pretty much game over for the transmission. It only a matter of time before performance of the transmission gets worse and worse. BUT that transmission is VERY easy to replace, i would check out a few trustworthy independent shops to give you a better price! I am usually a die-hard dealership, having been working at this jaguar land rover dealership for the last 2 years, but you are pretty much for sure going to be a cheaper price on the labor and like i said it is a pretty easy task.

My only precaution MAKE SURE IF YOU GETTING A USED TRANSMISSION THAT YOU GET SOME TYPE OF WARRANTY ON IT. Too many times have I seen customers loose thousands of dollars paying someone to put a used engine or transmission and have it fail almost right away.