ivane21

My sister took her truck to the dealership, they wanted $3000 to turn her brake rotors, replace an evap vent valve, replace a TPMS sensor, replace the converter and the headlight was separate at $400.
I fixed the headlight for about $95 from NAPA.
I did the front and rear brakes, replaced the rotors and pads.
She had the TPMS sensor fixed and reset, she could not wait for me..$135
I ordered the pipe, and it will be here in a few days, she took the truck to two different places and both said she needed a new converter, as you probably know just like my Tahoe, you need to replace both converters, not just one, so I told her to get all new oxygen sensors and air filter and plugs and wires and it will still be less than half of what they quoted her...

My question is about the vent valve, I had it at a buddys shop up in the air, I could not see it or the canister which may be soaked with gas, she said its getting very poor gas mileage. the dealer said exactly this:

VIN# 1GYFK63827R240384
PO449 EVAP VENT SOLENOID CONTROL CIRCUIT
PO430 CATALYST SYSTEM LOW EFFICIANCY BANK 2
NEEDS EVAP VENT VALVE AND WIRING HARNESS AND CATALYTIC CONVERTER

I found something up on top of the motor by the fuel rails that looks like a vent valve...my buddy said it might be on top of the gas tank.
Also, do you think its possible the converter might be good?, maybe the sensors are bad? I was told if they are the same, the numbers that is that the converter is not working, I will check them with my scan tool tomorrow. Any thoughts? Is the canister soaked with gas? can it be cleaned? Is there a purge valve as well? what about the solenoid? I have not dealt with this stuff much, I am sure short and long fuel trim is high.

Any help is sure appreciated.
Thanks,
Ivan in MN

oldgoat82

There was a lot in your post. I've done both the evap vent canister solenoid and replaced the cats on my 2007 Tahoe LTZ (146k miles). The vent canister solenoid is an easy fix...it sits above the spare tire on the frame...you gotta drop the spare to get to it. I had the P0449 code. GM made a change to the system that improved the vent filter at the end of the vent pipe, and takes it higher inside the well for the fuel tank fill. It's a one hour job. I bought mine at RockAuto.com. As for the cats, I had recurring P0430 codes and tried running the snake oil through the fuel to clean them up...didn't work. I moved O2 sensors around (right-left) and ruled them out as the problem. I broke down and installed Magnaflow direct fit cats (I already had a Magnaflow cat back exhaust.) The job isn't complicated, but take your time on the bolts at the exhaust manifold flanges. Kinda hard to get to...use some creative combinations of sockets and extensions. All 4 O2 sensors were still good...so I wouldn't throw $$ if you already know the cats are bad. New cats made a world of difference in performance...+3 mpg average. Only beef is that the wife doesn't like the rumble when decelerating or when the engine drops to 4 cylinder mode at highway speed...there's some resonance...so I crank up the radio to drown out her complaining. Good luck, Ivan. It's worth the time to fix it yourself.