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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15507
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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Jaguar X-Type gearbox fault p0171, 0174, 1643

Customer Question

Hello, im Fabian and i live in Chicago First all sorry for my poor English i'm going to explain my problem hope i can do it right I have a 2003 Jaguar X-type 2.5L awd 96,000 miles, the car got some problem 2 days ago i just arrived to my home and the car was running right but with the check engine light on from days ago, 1hr after i got to drive the car again, when i did the start engine on the gearbox fault message and cruise not available appeared on the dash, also headlight and the little red light in the gearbox does not works, the car is heavy or lazy now and when i open the hood i did smell like a burnt oil or something like that. A mechanic friend of mine has a $7000 diagnostic scanner because he works for a imported cars shop too and the scanner showed up 3 codes P0171, P0174, P1643, the mechanic told me about oil in the throttle and possible problems with the gasket I would like to find the possible problem of these codes and the gearbox fault message on dash and if there is any way to fix them outside the dealer or how much does it cost to fix it? I appreciate your atention Thank you very much Fabian
Submitted: 5 years ago.
Category: Jaguar
Expert:  Richard replied 5 years ago.

Hello Fabian and welcome to


We should also make sure you do not have a vacuum leak for the P0171 and P0174.. Start the engine and listen for a hissing noise while idling when the engine is cold. The PCV hose sometimes will split and the IMT valves sometimes leak. This will cause vacuum leaks. The PCV hose goes from the valve to the intake and the IMT valves are the electronic valves located on the right hand side of the intake manifold. I also see issues with the booster hose from the brake booster to the intake.


FOr the other code P1643 we should check fro water in the TCM. The TCM is located behind the driver side of the dash in the upper corner. Look under the dash and you should first see the auto wiper module if equipped. Remove the 10mm nut on that module and pull it down and out. Next you will see the TCM which is held in by two 10mm nuts. Remove the nuts then once the module is off the studs you can disconnect it. See if you see signs of corrosion in the connector or module.

Customer: replied 5 years ago.
Thanks Richard for you answer
A imported car mechanic has checked the car and he told me that the problem is between the TCM and transmission computer or something like that, he says he can fix the problem because he repair all car computer controls so i decided to wait what this guy can do
About the codes he said is the brake booster and also the car has problem with the brake it is like heavy, i have the replacement already so i'm going to change it too

Richard do you know the Mongoose JLR Diagnostic Programming?
Is it good to find some problems or codes in a Jaguar car?
Product features says: Use the Mongoose JLR directly with the software (available from Jaguar / Land Rover) on your own laptop or PC and see the same results the dealer sees
Is this true?

Thank you very much Richard
Expert:  Richard replied 5 years ago.
Yes the mongoose in the interface unit needed to communicate with your vehicle. It is the part that goes in between the laptop and your vehicle. You will need the software which is available through Jag part at a price. You can download it for free but in order to activate it you need to subscribe to the Jag site TOPIX. WIth the tool and software you can do everything a dealer can do.
Richard and other Jaguar Specialists are ready to help you
Customer: replied 5 years ago.
Thank you Richard so i think if i get the mongoose and i learn how to use it it is a good idea for the medium class people like me :-)

I forgot to ask this question before, i live in Chicago and my automatic x type 2.5 AWD is giving me from 13.6 to14mpg in city is it normal? i took the car to make a tune up 3 month ago but it still giving the same mpg i was checking the info about the mpg on this model and it is 17mpg in city, is there anything wrong or is it normal? the car has 96.000 miles

Thank you very much

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