Cheers,
I used a ScanGauge and pulled a P0442 (EVAP) code on my '99 XK8 27k miles. I read on this site that I should check the gas cap and I did and it seems fine. I also read that it could be a purge valve. I didn't pull any other codes and I cleared the P0442.

Does anyone know the location of the purge valve on the car? Also, before tearing into it; Is this the proper place to start?

Thanks in advance for your help.
-Craig

 

I should also add I had this in the shop before I bought it and they replaced the fuel pump and they said they pulled a code pointing to the Mass Air sensor. They replaced the sensor.
-Craig

 

I would first wait a few days to see if the code reappears. It could have been the filler cap was just loose at some point.

The system is located behind the inter left fender panel but you might want to get a copy of JTIS before jumping into it. Doesn't appear difficult and the parts prices quoted in related posts are under a $100 if I remember correctly.

 

There are many places for the EVAP system to leak. The fuel filler cap is the most common but faulty canister close valves sometimes do. I have found torn 'O'rings at the carbon canister(s) or lines/hoses to the purge valve. The most efficient way to diagnose an EVAP system is with a 'SMOKE MACHINE' to actually SEE the leak where the smoke escapes. It is a relatively expensive machine ($2,000.00+) so it is usually found at large shops in cities/counties/states where the emission laws are in force. You can call around to ask if anyone has this capability or check every connector and keep your 'sniffer' (olfactory sensor in the middle of your face) set for the usual gasoline smell in areas like the fuel tank or engine compartment.

bob gauff

 

Here are some old TSBs for more info

good luck with diagnosis
let us know what you find

bob gauff

 

Thanks for all the tips and help. After I re-seated the gas cap and have driven the car on 7 different occasions the check engine ligh has not come back on... knock on wood.

Thanks again,
Craig

 

After a reset, you may have to perform many "drive cycles" before the ECM recognizes a fault condition. The gas cap is usually not the problem. There are many locations that can leak in the Evap system. There is one particularly difficult junction of hoses just above the rear diff. You may want to ensure they are tight and not beginning to fragment or get brittle.

If it occurs again, a smoke machine is the only tru way to uncover these problems.

 

My '06 STR is doing the same thing. I replaced the gas cap with one I bought from the dealership. It lasts about a day or two then the code comes back. If I reset the code and drive on a long trip it will be fine for the whole trip till I start back with the city driving. I'm having trouble figuring out which parts to look at near the fuel tank. I've found multiple part numbers for what looks like the same part.

 

Hi Hollywood,
I'm having the same problem on my '03 STR. I had it "smoke tested" and they found no leaks. The pointed to the gas cap. I'm on my third one - #1 was a cheap aftermarket, #2 was a suspect OEM I purchased on line, and #3 I just purchased from the dealer. Nothing works. Please let me know how you were able to fix this problem. Also, how do you clear the code? Thanks for any and all help.

 

I've had the code come back everytime after resetting the code. I searched and couldn't find any leaks. I replaced the cap with a new one from the dealership. I ended up resetting the system by disconecting the battery and touching the pos and neg together to clear everything out. I've put almost 2,000 miles on it and about six tanks of gas and the light hasn't come back on.

 

Interesting. Is there a definitive consensus on this forum about the preferred way to effect the electrical system reset? Is this (above) it?

 

Bump.
I just received my smoke machine (Stinger Smoke Machine. About $150 on Amazon) and I traced my code P0442 to the Carbon Canister hose elbow right at the body of the canister. My system has two canisters. The leak was on the driver side (USA) canister.
Anyone know if that is just an o-ring seal or do I have to get a new can?

 

When I worked at the Jaguar dealer I had a leak (EVAP) at the carbon canister (X308) and it turned out to be a green 'O'ring on the plastic 'elbow' into the plastic housing.
I went to the parts dept to order the part. I had to order the ENTIRE plastic pipe from canister to engine compartment purge valve!!!!

The part came in and I removed the 'O'ring from the pipe assy and installed it on the car. I turned in the NEW pipe (several hundred dollars) with the OLD 'O'ring for warranty return.

I did not charge the replacement labor for the repair (I would have been 'back-flagged') because I did not install the pipe. I just charged diagnostic time and typed up a good story about emission testing for canisters and purge valve.

I probably could have dragged the plastic pipe around the shop a few times and sprayed water/dust on it to simulate use?? The replacement was a pretty big job compared to the 'O'ring.

There is sometimes no use in arguing with a bureaucracy like Jaguar Warranty.

Just replace the 'O'ring and recheck the leak!!!!

 

Good for you Bob, wish there were more people like you. Great story.

John

 

Awesomeness!

 

I want to thank all who contributed to this thread as the advice and o-ring fix, in the exact location as cyber3d, resolved a P0442 code on my 2000 XK-8 that had me really stymied for more than a year. I repaced the bad o-ring with an equivalent size ring from the hardware store (79 cents!) drove the car through the necessary drive cycle and the check engine light self-extinguished. No more code. Awsomeness for sure!

 

I use incense sticks to find vacuum leaks. A couple of them fired up in tandem produce enough smoke to usually find the leak. Of course there is always the old carburetor cleaner spray of WD-40 spray that have been used for generations. Most often you'll see the the sprayed liquid being sucked in and/or the engine increases in RPMs for a short few seconds.
--

 

I had this code come up two weeks ago. I read this thread and bought a genuine Jaguar gas cap for $50 and put that in. I didn’t even know my cap was supposed to have a cap tether until this one arrived. My cap was original with 199K miles on it. Put on the new cap and the check engine light has stayed off. Knock burled walnut…

 

in the “For what’s its worth” department :

Your gas cap seal will have a very long life if you give it a spray of silicone lubricant every time you fill up the gas tank. Without some rubber friendly lubrication occasionally the seal catches on the tank filler tube and the friction stretches it. Creating a situation where it fails to seal properly eventually.

WD-40 brand sells a silicone spray that is very inexpensive. The CRC brand of silicone spray is more expensive, but might last longer ……. Either silicone spray will not degrade the rubber seal.

Z

 

This has been a helpful thread, and I'm going through the same issue on my 2002 model. I ordered the smoke machine below, and it seems like a reasonable price and seems to get great reviews. Hopefully this will do the trick in finding where the leak is.