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Matt
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22145
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have 2010 jaguar XF going into safety mode while when i

Resolved Question:

I have 2010 jaguar XF going into safety mode while when i hit about 60mph.Diagnositic trouble codes showing 3 issues:
Manifold absolute pressure-mass or volume air flow correlation
Mass or volume airflow B circuit range/performance-air
Turbo/supercharge boost systemperformance.
Can you indicate what may be causing these codes to come. Mass ir flow meters have been change.
Thanks,
John
Submitted: 4 months ago.
Category: Jaguar
Expert:  Nicola-mod replied 4 months ago.
Hello,
I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.
I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.
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Nicola
Customer: replied 4 months ago.
I will wait 24 hrs for answer.
Thank you,
John
Expert:  Matt replied 4 months ago.

Hello

this sounds like a lack of boost pressure to me,

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.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues
Also have a feel around with your bare hands with the engine running to see if you can feel any escaping gas under your touch. Another method is to use a soap and water solution sprayed onto any suspect areas - if there's a leak it'll bubble up with the engine running

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

one other possibility is that the wastegate actuator spring has gone soft so allowing the wastegate to open prematurely - if your actuator has a threaded end you can increase the preload on it to see if this improves things otherwise these units are quite cheap compared to a new turbo so it may be worth trying a replacement

If this is OK then check for air leaks after the mass airflow meter - The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.
Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

Customer: replied 4 months ago.
Hi Matt,
I will pass on information to my Mechanic on Tuesday and hopefully get to bottom of problem.
Thanks,
John
Expert:  Matt replied 4 months ago.

no problem Jon

just get back to me on this post

Customer: replied 3 months ago.
Hi Matt,
Got my car back yesterday and problem fixed. It seems there was a crack in drivers side rocker cover causing a loss in pressure.
Thanks for your information.
John
John
Expert:  Matt replied 3 months ago.

glad to have helped John

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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22145
Experience: BEng hons Mech engineering, in auto industry 22 years
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