To my knowledge, there's no "check" to make sure the canister isn't clogged, outside of running diagnostic tests via SDD. As mentioned, all tests related to the fuel system passed. The tank was not dropped to swap the charcoal canister (it's not necessary) saving some labor hours.

I have the original canister sitting in my garage... If anyone has a confirmed bad one, we can both take measurements and compare results.

The specialist said this is a problem unique to NAS vehicles... But the only thing different on NON-NAS vehicles is the DMTL pump circuit, and fuel vapor exiting the system through the filler neck during refueling.


The right side port in the tank shown in Reply#72 is connected to a small tube that travels along the filler neck and vents the tank without restriction... Pointing to the LVS being the culprit for this problem.

It would have been nice if the specialist plugged the left side port and applied suction to the right side to see if air gets drawn into the tank via the fill port, but how many hours would YOU want to pay for a test to just say, "replace the tank".

Swapping a new charcoal canister is standard practice for the first step, with the lowest cost for labor and parts. Anything else requires the tank to be completely dropped, which means the drive shaft and everything else gets disconnected... It's a much bigger job than the charcoal canister alone requires. It was a gamble, and this time I lost.

 

Ah, I thought the tank needed to be dropped to get to the canister. It was mentioned in one of these fuel shutoff threads.

that should be about 1 hr of diagnosis but I get your point. It would have been nice if you paid for that test for us

And I really don't understand why Jaguar doesn't have a service document on this as it seems fairly common (at least here so maybe it's not all that common in the field?? )

 

also Traxtar, thanks a bunch for all these manual screenshots and diagnosis reporting!

So I've seen device, which I now know is the DMTL filter thanks to you, when I first started looking around at the problem but I couldn't get it off without risking breaking it. I was going to remove it and see if that helped with the fill up issue, assuming it was a clogged vent. I'll get back in there eventually but maybe someone ambitious can pop it off to see if the tank vents properly at fill up until then? Seems too easy...

 

Step 1 for me was to try & determine if the inlet check is valve sticking. So rigged up a funnel, theory being if the valve is sticking then fuel will back up the tube & overflow. The risk with this is overfilling the tank & flooding the evap canister, so I ensured the level was low enough. I poured 4 gallons down the tube as quickly as I could manage & it flowed freely. So this could be is a short term workaround for me, at the petrol pump.
looking at the photo of the evap canister it seems to have quick release fittings. Does anyone know how to release the fitting, do you depress the green tab? Also can the fitting to the tank be accessed without removing anything? If so I hope to disconnect & cap off the canister so air can’t be drawn in, but leave the tank breather open & try refuelling. That would rule out the canister, leaving just the separator in the tank.

 

I believe the fuel fittings all require a special tool to depress and side an outer ring, which releases the coupling.

 

Also when the specialist says the problem is unique to NAS vehicles, I have to disagree as I’m in the UK!