my sons 04 x tpe 3.0 has the 171 and 174 codes. it is running fine, and i wonder if it is a freak thing. can i clear the codes and see if they come back? how do i do this? i can find no vacume leaks anywhere. thanks bob

 

You need a code reader to clear the codes. If the problem is still there, the engine light will come back on. Also note if the problem goes away on its own (not likely) , the light will go off by itself after a certain period of time.

 

mphy98, the easiest way to clear the codes is to simply lift the negative battery lead off of the battery, wait a minute and then reconnect the battery lead. But, before you do that, please understand that you are going to loose all your radio presets and you will have to reprogram the windows (takes about 15 seconds a window to reprogram). Otherwise, you need to connect up a code reader and then you can erase the codes that way.

On a side note, our cars are set up to clear the codes after you have started the car 6 times and driven it for around 10 miles (16 KM) with the fault codes being clear the whole time. If at any point, the problem occurs again, the timer is reset and starts at that point. So, in some cases, the code can clear itself. But, like was said, odds are it will not.

As for that code, I would start with looking at the PCV hose running from the intake to the front valve cover (nearest the radiator). This hose is known to crack on the backside and is not visable unless you remove the hose and look on the back side. The second place to look is at the brake booster line running from the top of the intake to the brake booster. If you look at the center of the line, you will see a football shaped piece there, this is known to crack and cause a leak. The third thing I would tell you to do is to spend $5 (USD) on a can of Mass Air Flow (MAF) Sensor cleaner (not carb cleaner or any of the other similar spray cans). Now, remove the MAF sensor (right next to the battery, fitted into the side of the intake), use the can to spray the insides of the sensor and then reinstall.

Between these 3 things, odds are, you are going to clear the codes. Along these same lines, did you recently do a plug change on the car? If so, it is possible that your problem lies with the upper intake gaskets. They are cheap to buy if you know where to get them. If you go to Jag, plan on dropping a pretty penny for them.