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.

[Buckmark]

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

Ah yes, seen this before, more than a few times......what an honest thing to do.

Like this - Used car inspection for a customer, tipped off because the monitors were not set and the MIL did not illuminate with the key on (bulb check, also the 2 on the tach was slightly obscured.
Removed the cluster and found the cause....elec tape over MIL...

[Bean Counter]

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

Look: I asked for the opinions of mechanics, not medical doctors 

[Bean Counter]

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.

Thanks.

Reading this got my small brain working... Sometimes, when we park the car in the garage, there is a strong smell of gasoline after shutting the engine off. Could this be related?

[Bean Counter]

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..

I will. but, sorry to report: I did clear the codes, drive 150 miles, and go pass emissions 

I wrote the codes down and will go get it checked out. Its obvious causing me to lose fuel economy so I should get it fixed.

[jackelope]

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

Works perfectly if you want to drive around in a broken car.
 

[jackelope]

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..

I will. but, sorry to report: I did clear the codes, drive 150 miles, and go pass emissions 

I wrote the codes down and will go get it checked out. Its obvious causing me to lose fuel economy so I should get it fixed.

If the codes do not reset there's not a lot of point getting it checked out. Mostly, everything will test good.
Once something fails again, it will re-set the codes and turn the light back on. Once that happens, take it and get it checked out ASAP.
Sometimes EVAP faults are tough to accurately diagnose.

[Woodchuck]

 

[Bean Counter]

Yes, it passed. I've been through this before as I like to drive older, high mileage vehicles. Usually with oxygen sensors or catalytic converters--P0420 is a common code in these parts. While I believe in clean air and some pollution control standard, there's just a bad economic to the idea of being forced to spend $3,000 to keep a $5,000 car on the road as in the case of cat cons. I hope its not the case with the evap system but I loathe the idea of haphazardly ripping out parts and replacing them to 'see' if it fixes the problem.

[jackelope]

Yes, it passed. I've been through this before as I like to drive older, high mileage vehicles. Usually with oxygen sensors or catalytic converters--P0420 is a common code in these parts. While I believe in clean air and some pollution control standard, there's just a bad economic to the idea of being forced to spend $3,000 to keep a $5,000 car on the road as in the case of cat cons. I hope its not the case with the evap system but I loathe the idea of haphazardly ripping out parts and replacing them to 'see' if it fixes the problem.

I can get cat's done for $400 all day long.
 
You could almost name the car and I can get them done for that price.
 
Proper diag eliminates the need to shotgun parts to "see" if the problem is fixed.

[Bean Counter]

Well it has been a couple years but as I remembered the OEM cat cons from the dealership  have more heavy metals than the lower end after market ones that are just designed to get one through emissions. In fact, I got one done at a chop shop (Buckys) and it got me through emissions but two years later it was dead again. Seemed like if one is going to keep  a high mileage car they either have to shell out money for a cheap cat con every few years or nut up and get the oem one but that may not be the wisest choice for a car with 200,000+.

[Buckmark]

Yes, it passed. I've been through this before as I like to drive older, high mileage vehicles. Usually with oxygen sensors or catalytic converters--P0420 is a common code in these parts. While I believe in clean air and some pollution control standard, there's just a bad economic to the idea of being forced to spend $3,000 to keep a $5,000 car on the road as in the case of cat cons. I hope its not the case with the evap system but I loathe the idea of haphazardly ripping out parts and replacing them to 'see' if it fixes the problem.

I can get cat's done for $400 all day long.
 
You could almost name the car and I can get them done for that price.
 
Proper diag eliminates the need to shotgun parts to "see" if the problem is fixed.

toy Camry's, Hondas or any vehicle with the cat as part of the manifold or most cali Em cars 

[Buckmark]

Evap monitors are one if the pickiest to get to run on most vehicles without a means to run a self test.
Your evap monitors may not be set yet, driving 150 miles in one sitting wont do that, also fuel level has an effect and most can be 2 trip codes...

But congrats on getting a passing EM test and tabs...

[shadowless_nite]

Most likely one of the vsv are failing. Pull em out and bench test with a battery and alligator clips. Check for valves that don't click or flow according to the diagnostic tree posted up. Rapid taps with the alligator clips on the battery can sometimes get a intermittent one to fail on the bench for you. And don't buy a generic vsv. Get a oem or worst case scenario if in on a budget, lowball someone parting out on CL for a used since most those guys  don't care about little sensors and what not, and by lowball I mean a couple bucks. These parts interchange between quite a few cars with this family of motors.