The P0441 Thread

[gasman4u]

I'm of the uneducated opinion, that the evap/canister system in the 200 is flawed for very hot/high altitude environments.

Charcoal canister too low in relation to the tank? I don't know.

it's my understanding that the canister design is specific to the US market. Would be nice if someone could figure out how to fit the JDM or Middle East system without throwing codes.

I'm with you, as soon as temps are cooler, I get zero fuel smell. When it's ~110+, I'll get fuel smell and gurgling noises frequently. Winter = totally fine.

The design may indeed be different to meet epa emissions standards. Raising it would help. But only if it was significantly higher than our rigs (as in obscenely higher). If the other markets have another part number that would work with the us spec 200 series, this could prove quite the solution. Assuming it wouldn’t throw cel codes.

 

[Sajan]

P0441 generally takes a long time. The EVAP monitor has to run and complete, and that can take quite a while because very specific conditions have to be met.

Use Techstream, go to Engine ECM, utility, enable all readiness. Type in P0441 (select the “P” from dropdown menu) and check the judgement result.

If it’s not ready, you can run the EVAP utility. Takes 20-ish minutes and, if the system is operating correctly, will run the monitor and take care of removing the permanent status.

tried to run it first thing in the morning and got an error.

"Scantool could not activate the purge vsv, vent valve or vacuum pump"

 

[GrouchyTech]

tried to run it first thing in the morning and got an error.

"Scantool could not activate the purge vsv, vent valve or vacuum pump"

Try it in manual mode if it has the option

 

[Sajan]

Try it in manual mode if it has the option

The code eventually cleared. I have a log from a month ago that shows long term trims at -7 to -10% at most.

I haven't had any issues since then.....until last night. I was about 20 miles into a new tank of gas.
No codes, no light but when I was at a light I saw the idle dip/bounce.
When I got home I looked at the fuel trims and they are rich as hell. -18 to -24%..

Bad gas? I fill up at the same shell next to my house.
Bad EVAP purge valve?

 

[GrouchyTech]

The code eventually cleared. I have a log from a month ago that shows long term trims at -7 to -10% at most.

I haven't had any issues since then.....until last night. I was about 20 miles into a new tank of gas.
No codes, no light but when I was at a light I saw the idle dip/bounce.
When I got home I looked at the fuel trims and they are rich as hell. -18 to -24%..

Bad gas? I fill up at the same shell next to my house.
Bad EVAP purge valve?

Squeeze the hose running from the evap to the purge VSV and see how the fuel trims respond.

 

[Sajan]

Squeeze the hose running from the evap to the purge VSV and see how the fuel trims respond.

I might not be pinching it hard enough, but it didn’t seem to make a difference on either hose

EDIT: I swapped out the purge valve in the engine bay. didn't make a difference. both tested the same on the bench.

 

[Jason Andrews]

The code eventually cleared. I have a log from a month ago that shows long term trims at -7 to -10% at most.

I haven't had any issues since then.....until last night. I was about 20 miles into a new tank of gas.
No codes, no light but when I was at a light I saw the idle dip/bounce.
When I got home I looked at the fuel trims and they are rich as hell. -18 to -24%..

Bad gas? I fill up at the same shell next to my house.
Bad EVAP purge valve?

Saw another guy on the supercharged tundras thread with a SC '18 LX with 107k SC since 35k had the weird idle and PO441. Is this on your supercharged LX?

Coincidently I just recently had an erratic idle issue pop up on my '18 LX. The idle would drop really low, sometimes to 300 rpm but never died, and then in park one time I witnessed it rpm hunting and revving up over 1200 rpm all on its own. Bouncing all over the place in between, but otherwise drove fine. I never got any CEL's; but I knew something was up.

I decided to clean my MAF sensor and it's been fixed for about 2 weeks now. It idles noticeably more smooth and stable and the off/on throttle response while driving is noticeably more smooth as well. Truck has about 110k; supercharged since 55k. MAF looked super clean, but it seems to have done the trick for me. I also disconnected both my battery terminals while I did it to reset the ECU.

 

[GrouchyTech]

I might not be pinching it hard enough, but it didn’t seem to make a difference on either hose

EDIT: I swapped out the purge valve in the engine bay. didn't make a difference. both tested the same on the bench.

What is your evap purge learn value? (ECM data list)

 

[Sajan]

What is your evap purge learn value? (ECM data list)

I haven't filled up since so it's the same tank.
I did a few drives the last 2 days and nothing looks abnormal. I am thinking this is happening when I have a full tank. I don't top off and always stop at first shut off.

I need to go fill up and log all this again.

 

[GrouchyTech]

I'm of the uneducated opinion, that the evap/canister system in the 200 is flawed for very hot/high altitude environments.

Charcoal canister too low in relation to the tank? I don't know.

it's my understanding that the canister design is specific to the US market. Would be nice if someone could figure out how to fit the JDM or Middle East system without throwing codes.

I'm with you, as soon as temps are cooler, I get zero fuel smell. When it's ~110+, I'll get fuel smell and gurgling noises frequently. Winter = totally fine.

The EVAP will not perform the key-off leak-check above about 7,800 feet. It’s disabled because the pump would have to work much longer and that may burn the pump up.

 

[GrouchyTech]

I haven't filled up since so it's the same tank.
I did a few drives the last 2 days and nothing looks abnormal. I am thinking this is happening when I have a full tank. I don't top off and always stop at first shut off.

I need to go fill up and log all this again.

View attachment 4234243

Get your tank full and check again. If the fuel trims swing far into the negative, pinch off that hose between the charcoal canister and the purge valve. If your trim rises to your typical baseline then you probably have raw fuel in the canister. Do you top off the tank? Does the pump ever click off during fueling even though it isn’t full?

 

[Sajan]

Get your tank full and check again. If the fuel trims swing far into the negative, pinch off that hose between the charcoal canister and the purge valve. If your trim rises to your typical baseline then you probably have raw fuel in the canister. Do you top off the tank? Does the pump ever click off during fueling even though it isn’t full?

I don't know if the previous owner did but I never top off. I don't think it shuts off before it's full.
Will post an updated log after I go fill up. be back.