Logan5
Member
Got the P0446 code on a 2006 Tahoe so started the Evap Mystery Game. But since this truck is new to me recently and I haven't done any evap system work on it yet just decided to replace the 3 main parts that go wrong. Purge valve, Vent Valve, and the canister.
Bench tested the solenoids and put them in.
Cleared the code and decided to try this Service Bay Test on the tech2 clone I have. This keeps failing and says "Vent Performance".
I blew some air through from the purge line and air flows freely. I used the tech2 to run a evap seal and it builds vacuum as well.
Started digging deeper and checking the Fuel Tank Pressure, I am showing .9 V / 5 mmHg with the vehicle off. Should read next to 0 mmHg with the vehicle off. So I am leaning towards my FTP sensor is bad.
On the tech2 you can cycle up purge solenoid duty cycle and as I increase it the vacuum does build and the sensor does change. So it looks like the sensor is working properly, but it's just calibrated wrong?
I doubt the sensor can be recalibrated?
Looked for where that sensor is and its part of the fuel pump assy. Now it all sense. I just replaced the fuel pump, and (can you guess?)...I bought a cheap one off Amazon and not the 5x more expensive OEM or equivalent.
Kicking myself now. Guess I'll drop the tank (again) and swap out the sensor. That or eat it and get a whole new pump assy.
Figured I'd throw this out here first before I go drop the tank again.
P.S.Found this link informative (https://aviondemand.com/insider/pulling-codes-story-of-code-p0446/)
Bench tested the solenoids and put them in.
Cleared the code and decided to try this Service Bay Test on the tech2 clone I have. This keeps failing and says "Vent Performance".
I blew some air through from the purge line and air flows freely. I used the tech2 to run a evap seal and it builds vacuum as well.
Started digging deeper and checking the Fuel Tank Pressure, I am showing .9 V / 5 mmHg with the vehicle off. Should read next to 0 mmHg with the vehicle off. So I am leaning towards my FTP sensor is bad.
On the tech2 you can cycle up purge solenoid duty cycle and as I increase it the vacuum does build and the sensor does change. So it looks like the sensor is working properly, but it's just calibrated wrong?
I doubt the sensor can be recalibrated?
Looked for where that sensor is and its part of the fuel pump assy. Now it all sense. I just replaced the fuel pump, and (can you guess?)...I bought a cheap one off Amazon and not the 5x more expensive OEM or equivalent.
Kicking myself now. Guess I'll drop the tank (again) and swap out the sensor. That or eat it and get a whole new pump assy.
Figured I'd throw this out here first before I go drop the tank again.
P.S.Found this link informative (https://aviondemand.com/insider/pulling-codes-story-of-code-p0446/)
