My Jaguar xtype 2005 engine light is on and had someone run codes - said Bank one and two systems lean and PO171 and 174 - -the light came on several weeks ago and the import car place said it was the gas cap was loose. made sure it was screwed on tight but still have the light on.
Thanks!

 

Hi Cathy - I have moved your post from the General Tech section to the X-Type section for greater visibility/response

 

171 & 174= lean; to much air

Usually a vacuum leak.

 

Check for vacuum leaks. The items shown in this thread https://www.jaguarforums.com/forum/x-type-14/trouble-code-p0171-p0174-51596/ are common sources for leaks. are common sources for leaks.

 

+1
(and it's a zero not an oh, though commonly people do say oh)
Very fixable so don't panic. Don't leave it as leaks tend to cause catalytic converter damage if ignored.

 

Cathy, because you are getting both P0171 and P0174, odds are, you are looking at a bad PCV hose. You can check this yourself. Open the hood of your car. If you look, there is a big plastic cover over the engine. You will need to remove this (remove the oil cap, then there are 3 screws holding the cover down, a 90 degree turn disengages the screws, remove the cover then put the oil cap back on). If you look down in front of you, you will see a black box that says "Jaguar" on it. That is your air filter box. At the 2 o'clock position, you are going to see a large black hose coming out of it running back to the intake of the motor (large silver piece on top of the engine). If you look just to the left of that black hose, you should see a rubber hose about 1" in diameter running from beneath the air filter box and running back to the under side of the intake. Run your hand on the underneath side of that hose. Do you feel a split in the hose? If so, that is your problem. Also, if you look at this hose, is it smooth or is it ribbed? If you have a smooth hose, then that hose needs to be replace anyways as this is a known weak point of the car and if it isn't bad now, it can fail on you at any moment. If you are still unsure of whether the hose is good or not, you can pull one end off (just pressed into place and comes off fairly easy) and then lift the one end up to look at the underside.

If you are going to take the car to a shop, tell them that you are having a vacuum leak and that you want the following checked:

IMT o-rings
brake booster hose
PCV hose

Then finally, ask them to clean the MAF (mass air flow) sensor. It is possible that the sensor is dirty and simply cleaning that will clear your codes. If you have someone that is even semi mechanically inclined, they can do all of this for you for very cheap. ANy more questions, just let us know.

 

Agree. Here is a link of an article with a photo talking about P0171 and P0174 and their common problems:

jaghelp.com: Jaguar X-type common vacuum leaks. P0171 and P0174

Most likely a vacuum leak. I have one in the shop right now!

 

First off, find a different mechanic those codes have nothing to do with the gas cap.
You have a vacuum leak in the intake system.
I had the same codes in our 2003 and it was the O-rings on the IMT valves which cost around $5 if you do it yourself. I could hear the leak on mine.
As said by others the brake booster hose and PVC hose also can cause a vacuum leak.
Don't continue to drive in this condition because the computer is putting more fuel in to make up for more air coming into the intake through the leak. This condition isn't good, I know because I follow my own advise and after I replaced the O-rings it took me awhile to get everything cleaned out and my gas mileage back up to where it was before the leak.