Evap codes po440 and po101 what are they and how to fix

the most common causes are vent solenoid and fuel cap
P0440 PONTIAC code possible causes

• Missing or loose fuel cap
• Incorrect fuel filler cap used
• Fuel filler cap remains open or fails to close
• Foreign matter caught in fuel filler cap
• EVAP canister or fuel tank leaks
• EVAP system hose leaking
• Fuel tank leaking
• Faulty vent solenoid
• Faulty EVAP purge switch

https://www.justanswer.com/pontiac/9xoy3-2000-pontiac-montana-3-4l-check-engine-light-p0440.html

https://www.yourmechanic.com/article/p0449-obd-ii-trouble-code-evaporative-emission-control-system-vent-valve-solenoid-circuit-malfunction-by-spencer-clayton

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.
A code P0440 could mean one or more of the following has happened: The gas cap is not installed or working properly. The purge solenoid has failed. The canister is plugged and not working properly.
With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try: Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back. Inspect the EVAP system for cuts/holes in tubes/hoses. Inspect for damaged or disconnected hoses around the Evap purge solenoid ,Check and/or replace the sensor, Check and/or replace the purge valve, Have a professional use a smoke machine to detect leaks

broken evap line/port on fuel pump. Or leaking fuel pump o-ring
check the EVAP canister it is right next to fuel filter could be pcm needs update to fix false codes. Here is a old hillbilly trick that may help put saliva on the seal of gas cap when you fill up every time that may work for you.

code p0440 refers to evaporative emission (EVAP) system--malfunction===causes -hose connections--intake leak--EVAP canister
code po456 refers to the evaporative emission system--very small leak detected===causes --mechanical fault--hose---EVAP pressure sensor. The cracked hos may be the fault but I would be looking at the canister for the fault.

P0440 is the (PCM) and yout (EVAP) So look for a leak on the purge system. The P0453 is the same thing

Hello,

P0101 = Mass Air Flow (MAF) Sensor Performance
P0440 = Evaporative Emission (EVAP) System

I have had this problem before with trying to get my cars inspected. The easiest way I can suggest, is to bring it to Autozone or Advanced Auto Parts, and have them clear all your codes. Then put about 100 miles on the car of daily driving and bring it back to the same place to get it inspected. They should reinspect for no charge if you already paid for it.

I have noticed my check engine light going on when using the cheapest gas. Maybe try running a tank of the best stuff in there. At most, at least you will be cleaning your engine, and you will notice performance and gas mileage increases as well.

I hope this helps!


Mike

Most likely the gas cap is loose but, ....unless there is a hole in one of the evap lines or the fuel fill pipe, the most logical problems are the cap, the vent solenoid, and lastly the purge solenoid....

Take the cap off and re install it making sure it is tight and it clicks at least 3 times, drive tha car a while and after a certain number of starts and re starts of the engine the code should clear, if not then start checking the vacuum lines to the vapr recovery system as well at the gas fill hose and like I stated the last items will be those selenoids.

what code is it?po440,p0455?If it is one of those codes it means you have a large evap system leak not a vacuum leak by the engine.the evap leak is most likely a inop vent valve or a fuel cap not properly sealing.

it can be in 2 spots it is usually under the truck by the fuel tank a black boxy shape mounted to frame the other spot is behind the throttle body

P0440 - Evaporative Emission (EVAP) System


evaporative emission (EVAP) system has a large leak.
Check the gas cap or vent valve. these are the most common problems.


The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned. Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the Fuel tank pressure sensor (FTP). When the sensor indicates a small leak in the EVAP system, this code is set.


Here are some additional causes.

* A small leak in any of the EVAP hoses or fuel tank hoses
* A small leak in the purge valve or vent valve
* The EVAP Canister may be leaking