Check Engine Light: Evaporative Codes

[Bean Counter]

One of the drawbacks to cheap, high mileage vehicles 

Two questions:

P0440, 0441, 0446, are all evaporative. 0440 sounds like its more of a generalized code and it could possibly be the gas cap, but not 41 nor 46... unless 41 and 46 are caused by 40. Is this possible?

Are these codes just letting me know that I'm polluting a little more or is this causing a notable loss in fuel economy?

Thanks.

[Woodchuck]

Evap emmisions is the system the vehicle uses to dispose of excess fuel vapor.

[Bean Counter]

Thanks.
Yep. It sounds like it tries to send some of it back to be burnt off, so I'm wondering if its not doing that properly if I'm throwing fuel away? 

[Woodchuck]

That's correct, it likely has valve/solenoid that is not closing or is clogged. That system affects driveability 0
What type of vehicle?
The issue is that with the light is on if the vehicle is trying to tell you about something else at some point up the road, how do you know?

[Bean Counter]

02 Sequoia.
2UZ-FE motor
Thank

[coachcw]

toyota have a bunch of canister updates . I see vent valves full of dirt on trucks all the time .

[jackelope]

P0440 is a general evap system fault code. Pretty much sets because the other ones set.

P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

P0446 EVAPORATIVE EMISSION CONTROL SYSTEM VENT CONTROL MALFUNCTION


The vapor pressure sensor, VSV for canister closed valve (CCV), VSV for pressure switching valve are used to detect abnormalities in the evaporative emission control system.
 
The ECM decides whether there is an abnormality in the evaporative emission control system based on the vapor pressure sensor signal.
 
DTCs P0441 and P0446 are recorded by the ECM when evaporative emissions leak from the components within the dotted line in Fig 1, or when there is a malfunction in either the VSV for EVAP, the VSV for pressure switching valve, or in the vapor pressure sensor itself.
 

[Buckmark]

Toyotas atleast are very cooperative when doing evap diag as compared to some manufactures..

Get it diagnosed.. and please do not clear fault codes or disconnect the battery, that will erase freeze frame data that may be helpful in diagnosing the issue..

[jackelope]

Seems straight forward enough to diagnose. Surely no need to take it to your "Stealership" as you like to refer to them.

INSPECTION PROCEDURE

HINT:

•If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, first troubleshoot DTC P0441, P0446, P0450 or P0451. If no malfunction is detected, troubleshoot DTC P0440 next.
 •Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
 •When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.

[Fl0und3rz]

I love this site and its great members.

[Buckmark]

Come on jackelope, dont you just plug the thing in and it tells you whats wrong and what to replace 

[h20hunter]

Nope...you plug it in....ask parts for a P&A, they look up and order the wrong thing, it goes on backorder, tech digs in his box, finds a used part, installs it, customer pays full bore plus "shop fees", parts looses the order, forgets about it, part comes in, gets plussed into inventory, the stealership then sells it again when it is needed for real.

[jackelope]

Come on jackelope, dont you just plug the thing in and it tells you whats wrong and what to replace 

Normally we just google the code and throw some parts at it.

Nope...you plug it in....ask parts for a P&A, they look up and order the wrong thing, it goes on backorder, tech digs in his box, finds a used part, installs it, customer pays full bore plus "shop fees", parts looses the order, forgets about it, part comes in, gets plussed into inventory, the stealership then sells it again when it is needed for real.

 
It's almost like you work here.

[jackelope]

I love this site and its great members.

Me too.  Most of us are usually happy to help where we can.

[206]

Cover the check engine light with a little piece of electrical tape.