Driving today and check engine light came on. Engine is running smooth, checked all fluids and car is not overheating..running smooth.

Does anyone have any ideas on what is wrong?

 

Need to plug it in and get a code... This will give you a starting point at best. Sometimes the auto parts stores will do this for free or better yet, buy a cheap one for your own use... at least you'll be armed with info before going to the repair shop...

 

There was a software fault in some of the '09 cars. Some also needed replacement of a controller of the air injection pump.

Before you bother reading the codes just remove nd refasten th fuel filler cap. Three clicks minimum to ensure no air is leaking in

 

Thanks guys. Jagular, I tried your approach on the gas cap..but unfortunately the engine light is still on.

Isnthisncar safe to drive until I can bring it in to the dealer?

 

It will take a number of ignition cycles to reset after tightening the cap. Not going to go out immediately.

 

Code readers are cheap (relatively) and without a specific code (information) it's no different than parts diagnostic... A local AutoZone

Search: code | Code Reader | AutoZone.com

or similar store sells these for usually around $50 and up and it will give you an idea of the seriousness or non-seriousness of a CEL... The gas cap advice is valid but to check and be informed is your best bet...

Also, if the light is on constant it's not as urgent as if the light was flashing but it needs to be diagnosed none-the-less. I bought a code reader with diagnostics built in and it's been the best tool for all my vehicles (ODB II) as it gives me the power (knowledge) to point out to a service shop that I'm informed and know what the code is/means. Not to say shops are dishonest but it doesn't hurt to have some control rather than open wallet and fix at all cost...

 

I consulted my crystal ***** and you have a p0128, coolant temp below threashold from a torn t stat seal. You need a new t stat

 

No... that was me in 2010... haha

 

Just returned from dealership. Code P0171/P0174 indicated potential leak of gas fumes. The dealership performed smoke test and no leaks found. Cleared per bulletin JTB00118.

 

Do you have an r or normally aspirated? Thats a lean engine condition not gas fumes leaking.

 

If it is gas fumes leak then probably the gas cap was not tightened fully on one occasion. This code will clear itself after a few ignition cycles assuming the gas cap was to blame and is now tight.

It can be a momentary inattention that leads to failure to get those 3+ clicks needed to ensure the cap is on tight enough.

 

It was a lean engine condition as noted. I used the wrong terminology...so again, I want to thank all you guys who know their jaguars and can relay your experiences to non car guys lie me..I real appreciate it!

 

they just blew you off. they dont erroneously set. not those codes. again are you supercharged or not. Super charged cars have a issue with lean codes that are very hard to find until you know where to look. Like the oring that seals the brake booster ppipe to the intake to supercharger housing below the throttle body. I have another one right now to do and that 3 in a month.

 

Smoke test indeed!

This would be for intake leaks.

This means they are trying to trace an air leak into the engine.

The one Brutal has reported on several times is one they try not to find if the can talk you around.

 

Brutal,

I have a supercharged XF. What else would need to be done? What do I tell the technician? Is this going to be a recurring problem? Is this a dangerous problem?

Please advise


Ps..Jagular, please comment as well.

 

i would wager pens to peanuts that the leak is down at the brake booster pipe seal where it goes into the intake albow below the throttle body. Its right downstream from the EGR(hot exhaust gas) and with alittle time hardens the oring and is a nice big air leak. you dont notice any differance in running because the engines adds fuel to comphensate for this. But this is why the engine knows there is an air leak. have the short term fuel trims monitors while they spray this area with carb/brake cleaner propane etc.. theyll see the STFT(short term fuel trims) go -neg at the source of the air leak when sprayed. this is a L1 (advanced diagnosis) but any tech worth their salt should know how to diag a air leak. And if your working on Jags all day you start knowing where the problems keep hitting at.

 

It won't be dangerous but it should be repaired under warranty. I am only quoting Brutal because he seems so insistent that he knows. I'd be very interested to know if he is right this time also. If he is correct then your dealership owes him another beer.

 

Watchgeek, be sure to update your thread after you've driven 50-100 miles. It seems that the p0171/p0174 codes can resurface regularly even if they have 'cleared' the codes as you indicated.

I may start a thread on those codes also as my car is throwing them (just purchased used, have been searching and performing all the suggested checks from the forums on my own before I give up and let a shop do the harder stuff).

Hopefully in your case the codes don't come back!

 

ive had similar issue. CEL came on a few wks ago on a recently purchased 09 SC. Car was experience a rough idle cold.

tech came back with P0174. They tested and replace both air filters and monitored the fuel trims, still lean. then reset the adaptations, to normal range, and cleared code. so parts changed: seal-duc AJ86892; seal-outlet NCC7735BA, Filter C2Z15037.

now again this past weekend(under no CEL), and less than 1K miles later, the engine is idling rough cold again, there is a slight air knocking noise when driving & stopped, and under the hood(popped), air is blowing out with some force and audible noise.

brought in today to new service center, no fault codes came up. They physically can see and hear what I am experiencing. I'm told they are going to check system history.

any thoughts/input would be helpful

 

Is this seal issue common to the 4.2 and 5.0 L engines? Common to N/A and SC?