Guys,
Last year I have a P0456 "very small evap leak", replaced the Leak detection pump (Jaguar C2P3605), solved it and i passed emissions the error was clearly visible with a smoke test.
This year i have the same error again, sometimes it also triggers a "small leak" we did smoke test and couldnt find any leak.
What now? My mechanic cheated the system so we "pass" emissions, but next year i have to do it again so i want to fix it?
Where do you guys would start?
Obviously starting from cheap to expensive I guess..
Last year I have a P0456 "very small evap leak", replaced the Leak detection pump (Jaguar C2P3605), solved it and i passed emissions the error was clearly visible with a smoke test.
This year i have the same error again, sometimes it also triggers a "small leak" we did smoke test and couldnt find any leak.
What now? My mechanic cheated the system so we "pass" emissions, but next year i have to do it again so i want to fix it?
Where do you guys would start?
Obviously starting from cheap to expensive I guess..
tomfurie
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Mar 25, 2026
- Join DateSep 2010
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Any luck with the evap system?
How did you cheat the system? Would it work for Illinois?
I'd love to get my 2004 XJ8 VDP back on the road. It's has been off the road for years due to a "smallevapleak" that will not let the emissions cycle complete. It still runs & drives great.
How did you cheat the system? Would it work for Illinois?
I'd love to get my 2004 XJ8 VDP back on the road. It's has been off the road for years due to a "smallevapleak" that will not let the emissions cycle complete. It still runs & drives great.
I had that code before, the leak detection pump solved it.
But a year later I got it again, I haven’t tried to replace the leak detection pump since the part runs at $200 or so, replacement is not to difficult it’s at the rear axle. However I think the years before 2006 don’t have the leak detection pump.
The years before sometimes have a failure at the purge valve (see )
I think Jaguar part number is: c2c21972
Actually in Wisconsin you cannot pass the emission test if a test is incomplete or failed, but if it is delayed it can passed, my mechanic had a way to basically cheat the emission system and loop it, that way it actually no says “delay”, unfortunately he wasn’t willing to share the details. Since he did it the evap 0.020” leak test cycle never ran again (I have a obd reader and can see that). Sometimes a gas cap could leak too but actually not very common on the jag.
Another way to solve it is to move to an actual state where you have freedom and not elites pushing you to buy new cars with some crazy emission tests that **** down good running cars that are actually really good on gas like the xj8! I just moved down to Missouri, being a free man now and enjoy my nice jag on the nice roads in the Ozarks!
But a year later I got it again, I haven’t tried to replace the leak detection pump since the part runs at $200 or so, replacement is not to difficult it’s at the rear axle. However I think the years before 2006 don’t have the leak detection pump.
The years before sometimes have a failure at the purge valve (see )
I think Jaguar part number is: c2c21972
Actually in Wisconsin you cannot pass the emission test if a test is incomplete or failed, but if it is delayed it can passed, my mechanic had a way to basically cheat the emission system and loop it, that way it actually no says “delay”, unfortunately he wasn’t willing to share the details. Since he did it the evap 0.020” leak test cycle never ran again (I have a obd reader and can see that). Sometimes a gas cap could leak too but actually not very common on the jag.
Another way to solve it is to move to an actual state where you have freedom and not elites pushing you to buy new cars with some crazy emission tests that **** down good running cars that are actually really good on gas like the xj8! I just moved down to Missouri, being a free man now and enjoy my nice jag on the nice roads in the Ozarks!