Just thought I would share what I went through and what actually solved a pesky P0456 Evap Small Leak I was getting on my 2006 X with 4.0L engine.
For information, according to the manual, the test for the evap system will only run on a cold start and only if the fuel tank is somewhere between 3/4 and 1/4 full.
I was intermittently getting a check engine light with the dreaded P0456 code. It would only happen when my gas tank was somewhere between 1/2 and 1/4 tank full.
First thing I tried was replacing the gas cap with a Mopar gas cap. It didn't fix the problem.
Next, I bought a smoke tester and smoked it three separate times, not finding any leaks. I would hook the smoke tester up at the vacuum line at the purge solenoid in the engine compartment. I also hooked up the smoke tester back at the evap canister located in the right rear wheel well. There was never any leaks in the system and the system would pressurize up fine with the smoke tester.
I visually inspected all the vacuum lines from the engine bay, all the way along the frame, on top of the fuel tank, and around the Evap Cannister. Nothing, everything looked good.
Out of frustration, I finally decided just to replace the Natural Vacuum Leak Detection Pump (NVLD).
I'm happy to report that two months later and the Evap system has been working properly and have not had any check engine light.
For information, according to the manual, the test for the evap system will only run on a cold start and only if the fuel tank is somewhere between 3/4 and 1/4 full.
I was intermittently getting a check engine light with the dreaded P0456 code. It would only happen when my gas tank was somewhere between 1/2 and 1/4 tank full.
First thing I tried was replacing the gas cap with a Mopar gas cap. It didn't fix the problem.
Next, I bought a smoke tester and smoked it three separate times, not finding any leaks. I would hook the smoke tester up at the vacuum line at the purge solenoid in the engine compartment. I also hooked up the smoke tester back at the evap canister located in the right rear wheel well. There was never any leaks in the system and the system would pressurize up fine with the smoke tester.
I visually inspected all the vacuum lines from the engine bay, all the way along the frame, on top of the fuel tank, and around the Evap Cannister. Nothing, everything looked good.
Out of frustration, I finally decided just to replace the Natural Vacuum Leak Detection Pump (NVLD).
I'm happy to report that two months later and the Evap system has been working properly and have not had any check engine light.
