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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 24232
Experience:  BEng hons Mech engineering, in auto industry 22 years
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On three occasions over the past 2 - 3 weeks my 08 Jaguar

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On three occasions over the past 2 - 3 weeks my 08 Jaguar X-Type has shown flashing coil light and the message "Transmission Fault" on the mileage slot. After a rest all reverts to normal. The local Jaguar agent had it over 13th and 14th Sept and computer diagnosis said replacement turbo required at total cost of £1884 including discount required. I had it away this past weekend (15th to 17th) a total of 310 miles with no problem.
What is the diagnosis and what should I do? Certainly. when the message "Transmission Fault" going up hill is a problem.
The car is Jaguar X-Type, 2.2 D, 63,000 miles.
Customer: replied 1 year ago.
Automatic transmission
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call.
Customer: replied 1 year ago.
Let me know if you need more information, or send me the service offer(s) so we can proceed.


a flashing coil light does mean an engine fault

and I've known to get transmission fault messages when you're down on power as the transmission control isn't seeing the torque its expecting to see.

I'd first check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.

Also check that the vacuum hose running to the dump /or turbo bypass valve is intact with no leaks as if the dump valve is opening prematurely you'll be losing all your boost

If this is OK then remove the high pressure intake hose after the turbo and have a feel of the turbine wheel - there should be no play radially at all - but a little bit of axial / end to end float is normal

The dump valve is on the turbo boost air (post compressor) side its there to blow off or 'dump' the excess boost pressure you get when you close the throttle ( like just before a gear change)
the important thing with a dump valve is that it seals properly when its not being operated if the valve has a torn seal or a broken spring then it'll blow off before it should and you'll lose boost pressure

this video shows how you can test it

if this is all OK then I'd say the issue is with the turbo actuator

they can burn out so its worth popping the lid off the actuator and checking inside

I've attached an image of a faulty actuator and you'll see the solder joints are burned

sometimes they can be brought back to life by resoldering the joints

Customer: replied 1 year ago.
Careful reply full of excellent information. But I shall check that the Jaguar agent has done the proscribed examination.


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