How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22903
Experience:  BEng hons Mech engineering, in auto industry 22 years
Type Your Jaguar Question Here...
Matt is online now

I have a 2008 jaguar sovereign LWB diesel. Unfortunately the

This answer was rated:

I have a 2008 jaguar sovereign LWB diesel. Unfortunately the car was accidentally filled with petrol and driven for a mile or two down the motorway before it spluttered badly and was parked on the hardstanding. The AA was called and they transported it to a local garage who removed the petrol and filled it with diesel. However the restricted performance stayed on The car drove smoothly with the restricted performance for 100 miles to get home without problems other than the restriction. What damage would have been done that keeps the restricted performance light on. When my wife did the same thing on a Mercedes A class and drove for about a mile all was resolved by the AA removing the petrol and refilling with diesel and the car has worked fine since then.

there's a fuel quality sensor on the Jaguar which would have had a minor fit when it was exposed to the petrol

as a consequence its likely that the car will need plugging into a diagnostic device to read off the stored fault code and clear any faults

this will also show up if anything is at fault as its possible that the main fuel pump or the injectors may have been damaged

so I'd suggest this as the next step

also its well worth using a Jaguar specialist for this as you need the Jaguar diagnostic tool to ensure the code isn't misinterpreted

you don't need a dealership ( and their high costs) but a independent Jagaur garage should be able to help
Customer: replied 3 years ago.

Thank you for your response.

I have tken the car to a Main Jaguar garage and their Jaguar disgnostics have come up with the 2 turbo units need replacing with diafram and software

Totalling £3,300 plus the £324 for the 2 diagnostics ! ouch

None of the points you mention have come up. Though I suspect the car would not have run as smoothly in restricted performance mode if the points you mentioned were indeed damaged.

This is the first time I have used this Jaguar garage.

They are bona fide and show up on Jaguars web site.

Is this consistent with the incident ?

The car always ran superbly prior to this incidence and is in superb condition. So much so that I have chosen to keep it rather than go for the newer model which I do not like the look of at all.

It was previously serviced looked after at an independent Jaguar garage near Liverpool with all the Jaguar diagnostics.

I am now in London, and would like to find a good independent jaguar garage to use in the future without having to go to my merchant bankers every time it goes in. Any suggestions.

Should I be confident with the jaguar garage's apparent diagnostic findings do they make sense in the context of the incidence that my Australian Brother, who had borrowed the car, has last night filled me in with?

all the best


Hello Leslie

just filling up with diesel should not have damaged both turbos? turbo tend to get damaged by over-revving the engine or getting it far too hot

of course they do wear out over time as well so this could just be a coincidence that the restricted performance occured at the same time, but the diagnostic check doesn 't really stack up with it just being misfuelled

as for the London specialist


Matt and other Jaguar Specialists are ready to help you
do you still need help with this?
Customer: replied 3 years ago.

No I do not need further help, thank you for asking. I am glad to say that the car now runs perfectly having replaced the Turbos.

It would seem to have been a coincidence.

I do alot of travelling with the car and it has done some 90,000 miles so presumably the turbos were perhaps past their best.


glad you got it sorted