P0455 Evaporative Emission Control System Leak Detected (gross leak)

[AmsterDutch]

Okay I have a P0455 code that keeps triggering the MIL and I have a warning for Fuel cap ...so I went and bought a new Fuel cap from RockAuto and realized that there must be two different styles because the first one I ordered was a Gates Brand but it didn't fit ...So I then realized the gas cap has Threads on it and ordered a Motorad Brand ...well long story short I still get the Fuel cap warning on the dash once in awhile...and the P0455 code is tripping my Check Engine Light every so often...It says that there is a large leak in EVAP ... indicator on dash says " check gas cap " Does this car work with OEM gas cap only or does aftermarkets work? Thanks everyone

 

[joegr]

I don't have an answer to your question, but I can say that your problem is unlikely to be the gas cap. Those seem to be pretty reliable. It could be a hose, fuel pump ring seal, or even a solenoid valve.

 

[AmsterDutch]

I don't have an answer to your question, but I can say that your problem is unlikely to be the gas cap. Those seem to be pretty reliable. It could be a hose, fuel pump ring seal, or even a solenoid valve.

How likely would it be the FPS (Fuel Pressure Sensor) I guess what I'm asking is .... is this a pressure sensor code?

 

[joegr]

How likely would it be the FPS (Fuel Pressure Sensor) I guess what I'm asking is .... is this a pressure sensor code?

Not normally, AFAIK.

 

[AmsterDutch]

Not normally, AFAIK.

Ran some tests on Forscan ...mostly fuel line pressure tests and everything tested out good...so you were right it's not FPS related ...my next question is when I tested the Fuel Tank Pressure sensor it stayed a steady 1.0 reading ...is this normal?

 

[04_Sport_LS]

Didn't you have this problem once before, (tank pressure)?

Didn't you also in the past... have a problem with a leak at the sending unit?

Maybe you're having another issue with the lock ring and gasket.

 

[04_Sport_LS]

Usually the gas cap is the cheapest and easiest attempt at a "quick fix"... and most of the time it works. However... it might not still be getting a good seal.

I have noticed at times when I fuel up... that there is very little drag on the gas cap gasket when twisting the cap back on.

When I look at the filler neck there is a bunch of dark crud on the neck. I'll then wet a paper towel with winsheild cleaner at the gas station... and clean the neck and gasket... then dry with another paper towel.

 

[AmsterDutch]

Usually the gas cap is the cheapest and easiest attempt at a "quick fix"... and most of the time it works. However... it might not still be getting a good seal.

I have noticed at times when I fuel up... that there is very little drag on the gas cap gasket when twisting the cap back on.

When I look at the filler neck there is a bunch of dark crud on the neck. I'll then wet a paper towel with winsheild cleaner at the gas station... and clean the neck and gasket... then dry with another paper towel.

Nope never had this problem on my 2001 LS ...that was the fuel pump assembly connector ...it broke and I finally had another member send one my way and problem was fixed ...this code pops up randomly ...it doesn't effect the driving ...just want it fixed once and for all...I will keep tracking it down with Forscan...this app is amazing