2002 prizm with p0440 code

P0440 = Evaporative Emission System.
P0441 = Evaporative Emission System Incorrect Purge Flow.
P0446 = Evaporative Emission System Vent Control Circuit.
The vehicle is fitted with a system that recycles unburnt fuel in the exhaust gases, usually referred to as the EVAP system. This sounds like a possible issue with the valve built into this system.

code p0440 refers to evaporative emission (EVAP) system--malfunction=== causes --hose connections --intake leak--EVAP canister purge valve
code po441 refers to EVAP --incorrect flow detected==causes the same as for po440
code po446 refers to EVAP system vent control --circuit malfunction===causes --wiring---EVAP can purge valve--ECM
generally I would replace the purge valve as it is common to all codes

P0440 Evaporative Emission Control System Malfunction P0441 Evaporative Emission Control System Incorrect Purge Flow P0446 Evaporative Emission Control System Vent Control Circuit Malfunction

• 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

Easy fix? Replace your gas cap.

yes it would be a smart thing to do and no it is not that hard it should onlt have two bolts holding it on

where is Evap Emission Control System Purge Flow fault

P0440= Evap Control Sys Malfunction
P0441= Evap Control Sys Purge Flow Fault
P0446= Evap Control Sys Vent Ckt Malfunction

i have 2003 trailblazer ltz 153 000 mileage i have code po440 .i changed gas cap and turned off the chech engine light... i made 300 miles and it was good and today morning i drove a mile and light turned on ..... what do i have to fix ...thanks

Yes it would cause these Codes.

These codes are all for the Evaporative Emissions System.

P0440- Evaporative emissions system fault- just saying there's something wrong with the system.

P0441- Evaporative emissions system- Incorrect purge flow- saying that the system isn't purging the raw fuel vapors (hydrocarbons- HC) as well as it should.

P0446- Evaporative emissions system- Control valve circuit low- there is a valve, usually located on the charcoal canister at the rear of the vehicle, that opens to allow fresh air to enter the evaporative emissions system as the engine vacuum purges the fuel vapors from the charcoal canister and closes when purge is not needed to prevent leakage of those fuel vapors to the atmosphere (HC is a greenhouse gas and is regulated as such by the fed gov't).

Given that you have the incorrect purge flow code and the control valve code together, my bet is that the vent control valve has failed (causing the P0446) and is not opening to allow fresh air into the system to displace the air from within the system that is being pulled to the engine. Since you have no fresh air entering the system, the engine will pull a vacuum on the system instead of the vapors "flowing" into the engine (causing the P0441).


I hope that this is helpful to you!!!


ASE Master Technician with L1 and X1 Certifications; Nissan Scope Technician; Chrysler Level 3 Silver Technician- 12+ years experience.