P0455 EVAP LEAK - Cap, Solenoid, Vent Valve No FIX...

KNBlazer

Well-Known Member
2004 TB EXT 4.2 LS - I have replaced the Gas Cap with an AcDelco, replaced Evap Vent Valve, & Evap Purge Solenoid... Solenoid replaced it last night, disconnected Battery for 30 minutes, cleaned throttle body... this morning light came back on.... I have purchased a Smoke Machine and an Evap boot cone a few weeks back in anticipation that the parts replaced would not fix my issue... I have emissions testing in February and can only work on the truck on the weekends due to work... Any tips are much appreciated..

I also purchased the Canister, but it looks like the tank has to come down, am I mistaken?

The boot I purchased for the gas tank...

.20181216_104128.jpg
 
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gpking

Well-Known Member
I assume you've visually inspected the filler neck too?

The tank seemingly needs to come down to get to anything on the top except the pressure sensor which is on the rear for some years (that's all I've had to replace on mine and never dropped the tank, it caused a P0440 "pressure too low"). Checking with smoke machine is a good idea. It could be anything once those usual suspects are ruled out.
 

Mooseman

Moderator
Since you do have the smoke machine, might as well use it instead of just throwing more parts at it.

Just one thought. One thing that might throw it off is if the pressure sensor is not working correctly and erroneously reporting no tank pressure/vacuum. If you have to drop the tank, might as well replace it.
 

MRRSM

Lifetime VIP Supporter
Before you Pull the Evap Charcoal Filled Canister... Did you also replace THIS component as well?

EVAPEMISSIONSCANISTERPURGESOLENOID.jpeg
 

MRRSM

Lifetime VIP Supporter
This Video may prove helpful even though you may NOT have an expensive Snap-On Verus Scanner... it may point you in other directions that are much more 'granular' and perhaps they have not as yet been investigated:

 
OP
OP
KNBlazer

KNBlazer

Well-Known Member
I assume you've visually inspected the filler neck too?

The tank seemingly needs to come down to get to anything on the top except the pressure sensor which is on the rear for some years (that's all I've had to replace on mine and never dropped the tank, it caused a P0440 "pressure too low"). Checking with smoke machine is a good idea. It could be anything once those usual suspects are ruled out.
Just replaced FTPS an hour ago, took it for a spin, got back home, SES light went out on its own... light has been on since July... bulb still works, I checked.... 🤣🤣🤣🤣
will update if light comes back... Cleared stored code w/ scanner, cleand Throttle Body, disconnected battery, and that's a wrap...
 

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