I bench tested the charcoal canister vent valve an works as it should
new charcoal canister
0 volts coming out of the vent valve even when I command it to be on or off from my computer .
wondering what could be the problem im wondering if the white wire is broken somewhere in the line .unable to check it bc I'm not sure where the white wire ends at ..if it ends at the pcm which pin is it so I can just jump a wire from the pcm to the vent valve .... in search of wire diagram of evap wire an pin Diagram for the pcm ... has to be same year an ment for my truck do not wanna burn up another pcm . Please help

 

Here you go (attached). PCM is on pin 45 of C2 connector.

Valve has 12V to it on Orange wire at all times. On/Off Control is by the PCM grounding (or not grounding) the circuit through the white wire.

 

Still have p0449 popping up I even jumped from the pcm to the plug to the vent canisters an it's still popping a e-check light I'm super confused on this e-check light please help solve
the truck is a 2004 blazer ZR2

 

Hello: Did you ever find a solution to your P0449 code? I am up against the same issue, and building a smoke test machine to run on a 2005 ZR2. All

components and wiring have tested good to this point but the code still keeps popping up!

 

There is no single solution to this or most trouble codes, proper diagnosis or the parts cannon is required.

1. Have you replaced the gas cap? Sometimes this gets you there.
2. Do you have a scanner that can command the evap solenoid? If so can you hear it clunk?
3. Inspect the charcoal cannister, vent hoses and solenoid electrical connections.
4. If your a parts cannon guy replace the evap solenoid, if you want to do a proper diagnosis, grab a DMM and a test light and report back

George

 

Wow, thats quick! Thanks
1: gas cap replaced ( GM part, not off shore)
2: yes, purge solenoid and canister solenoid working ( wiring to components lights up as well under command tests) I have scanner capable of active testing
3: All componenets seem to be in good shape as well as electrical and hose connections
4: Currently fudging together a smoke machine to test diagnostic port...( truck was bought from young fella who tried his best to beat it to death...I have cleaned up all his damage and bad repairs or no repairs) just this one P0449 code left. This has left me scratching my head. Will follow up after smoke test

 

Is there any history on the fuel tank pressure sensor or its circuit?

George