1997 Jaguar XJR trans shiftted to limp home mode & trou

  • 1997 JAGUAR XJR

Computer problem
1997 Jaguar XJR 6 cyl Two Wheel Drive Automatic 160000 miles

scanner showing DTC P1777 and trans in Limp Home Mode. How can I get the trans back to normal mode.
My snapon scanner will not clear code.
What is yhe repair procedure?

Do you
have the same problem?
Monday, October 5th, 2009 AT 8:34 PM

1 Reply


I came across this very same problem just the other day on a customers vehicle. Basically what that code is, is a manufacture specific code. If you look in to it a little bit more its a code having to do with ignition timing. So why the limp in mode? So first things first, check your basics, Check ALL your fuses in all of your fuse boxes, in that model there are 5 fuse boxes. Two in the engine bay two behing the kick boards under the passenger seat and the last one in the trunk. If ok, then check all of you electrical connections and any obvious shorts that there may be in the wiring. Then check and see in side your transmission for any busted pieces or chucks of metal. If there are any then your SOL and you'll have to replace the tranny costing well over four grand. Fortunatly those trannys are pretty tough and you don't see them fail often. SO. If all those things check out. Nine out of ten times you will need to replace your TCM (transmission controll module) with the new software updates. Reason for this is there is a glitch in the software in the TCM. So when the TCM goes to the ECM (engine controll module) to request information about egine load so the tcm can tell the trannsmission how to perform, the glitch keeps the TCM from doing so. AND that is why an ignition timing code would put your tranny into limp in-mode. And if you have the p1775 code in there as well that pretty much seals the deal. Go get a new TCM

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Thursday, October 29th, 2009 AT 6:09 PM

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