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Gary
Gary, GMC Technician
Category: GM
Satisfied Customers: 15900
Experience:  15 years gm master tech/15 years ASE master tech
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1999 Chevrolet Suburban 118,000 miles C1500 2wd SES light

Customer Question

1999 Chevrolet Suburban 118,000 miles C1500 2wd
SES light on trouble code P0446
Where is the solenoid for the EVAP system located? What is the fix for this code?
Replace the solenoid? There are many fixes for Silverado Pickups online but not for Suburbans
Removed Solenoid under the hood on the canister, cleaned solenoid with compressed air and WD40, replaced solenoid. Disconnected battery to clear code. Started this morning and light came on again.
Submitted: 3 years ago.
Category: GM
Expert:  Gary replied 3 years ago.

Welcome to Justanswer ! my name is XXXXX XXXXX i will do my best to assist you with this problem

this code is usually one of 2 things its either the vent solenoid bad near the fuel tank or the fuel tank pressure sensor plugged into the top of the fuel tank that tells the computer what the fuel tank pressure is inside it when the computer tests the fuel tank system for any leaks

so either the tank pressure sensor is bad and sending a wrong signal to the computer or the vent solenoid is not venting when it should or not closing when it should for the evap test

is this something you are going to try to fix yourself ?

or looking for a very good idea before it goes to the shop ?

Customer: replied 3 years ago.
I have removed the gas tank before on another Suburban I used to own.
I don't think I want to do it again. I can pay my mechanic to drop the tank and replace the tank pressure sensor and the solenoid just to be sure. That way I don't have to pay twice to remove the tank. You said the solenoid was near the tank. Do I have to remove the tank to replace it?
Expert:  Gary replied 3 years ago.

you usually can drop it down or lower it enough to swap out the tank sensor

it sounds like you already changed the vent solenoid off of the canister already

if the connector to that is good and the 2 wires replacing the fuel tank pressure sensor should correct this code

# XXXXX in this picture is the tank sensor

 

 

Customer: replied 3 years ago.
I haven't replaced the vent solenoid on the canister assembly. I just cleaned it and replaced it. Anyway to test it?
I know where that fuel pressure sensor is from taking the tank down before. I might be able to remove it without taking the tank out completely.
Expert:  Gary replied 3 years ago.
the only way to test it is to turn it on and off with a scan tool connected to the truck and see if it will open and close when commanded open and closed
Gary and other GM Specialists are ready to help you
Customer: replied 3 years ago.
I happen to have a fuel pressure sensor from the other Suburban I had. I am going to buy a canister purge solenoid and change them both.
Thanks for your help.
Expert:  Gary replied 3 years ago.
any time
Customer: replied 3 years ago.
I had Auto Zone put a scan tool on it and it came up fuel pressure sensor
Expert:  Gary replied 3 years ago.
ok replacing the sensor should correct this code for you