(Solved) Persistent P2420 code (and rare P0441) with no aux fuel tank. (1 Viewer)

[mcmarshing]

Note: I will add more details, and some more of my thought processes later when I have time - I figured I would just put this out there to see if anybody has experienced this and can speak to it for the time being:

Posting up here to see if anybody has had any issues with getting P2420 codes overnight and/or has gotten a P0441 code while driving WITHOUT a modified fuel tank/aux tank. I recently moved to NC (sea level) from UT (5000ft+) and ever since moving here, maybe once a week I'll get a P2420 code. Since having the 200 here in 2024, I have gotten a P0441 maybe 3 times randomly only while driving. I have replaced the fuel tank cap (OE). For what it's worth, I bought OBD Fusion with the car specific stuff and I've attached a screenshot of what it looks like on the rare occasion both codes pop.

The OE troubleshooting is very extensive, and I did do a VSV valve check (which worked), but I since lost my cable and haven't gotten techstream to work with a new cable (should be an easy fix). But, I've been slammed with work, and it's just been kind of tough to just "remember where I left off" let alone go through a pretty intensive procedure. I flipped through the OE manual, and glanced over the charcoal canister's troubleshooting procedures, and it seems like if it is faulty, you have to replace it anyways.

So, i'm leaning towards just ordering a new canister. And when I have time, just throw that thing up there and hope it fixes the problem. Save time on my side troubleshooting. I did do a visual inspection of everything down there, and didn't see any obvious signs of wear or disconnects.

But, my question is, does the canister pump module and everything else in the canister something that just "goes bad"? I saw in another thread that someone had water leaking down from a breather tube, causing corrosion, leading to pump module failure. Everything else I've searched on here usually has to do with 2nd order effects after an LRA tank, and I just wanted to see if anybody with an unmodified tank has had this issue.

Any help is appreciated. My wife drives the 200 at times too, and I'm inclined to get it fixed so she doesn't lose traction control or just randomly freak out when she is using the vehicle.

 

[gasman4u]

idk that traction control is lost when this CEL comes on. I think cruise control is the only thing that is impacted, but I will confirm the next time it happens to me.

I'm still trying to get my techstream laptop to work given all the new nanny controls on the newest windows variant. very frustrating to have technology be a hindrance vs augmentation.

 

[mcmarshing]

Well, I've changed out the charcoal canister, the evap valves on top of the intake manifolds (25860-0S020 and 25860-0S010), had no CEL when I fired it up this morning, but had a P2420 code pop up when I started it back to leave... I'm hoping that it's just the change in pressure caused by me swapping out the VSV valve (one of the hoses had some decent negative pressure to it), and the ECU measuring some whack extra high reference measurement.

Looks like I also have to find a cable to Techstream connected and do the full troubleshoot procedures otherwise.

 

[bloc]

If you invest in techstream avoid the “miniVCI” versions of the cables. Known to cause problems with live data and TPMS programming.

The VCX Nano versions are more expensive (though still reasonable) and do support these features.

 

[mcmarshing]

Good to know about the miniVCI cables. I got a second one off Amazon that IS a miniVCI branded one that works... But, whenever I get around to doing live testing and it's not working, i'll for sure be buying the VCX nano version.

Anyways, I finally got time to get Techstream running. I didn't have a ton of time to do the full diagnostic, but I wanted to at least get values and stop the no-seatbelt-chime and stop the telescoping steering wheel. I'm not gonna lie, the valve being "off" means open or closed, or "on" means open or closed confuses me, so i'm going to have to sit down this weekend and re-read the manual's definition of the P2420 code. post vacuum pressure is reading 0.28kPa-g, and the minimum limit is 0.3kPA-g - a frustratingly close value to reaching the minimum to NOT pop a DTC code.

 

[prharper]

I've had the P2420 come and go randomly for at least two years now.

I have a LRA 24 aux tank and I never overfill, always stop at the first click at the pump.
The last permanent code was a persistent one. Started in the early spring and was able to get it to reset/clear on its own after a month or two.

Fast forward.

It came back just before I started a trip from VA to CO at the end of July. I attended two organized events (Cruisers on the Rockies and LCDC). After day 1 or day 2 on the trails, the P2420 permanent code disappeared.

Ironically I was talking to Ben and Christo of Slee the night before during the whiskey tasting about the LRA and Pxxxx codes. During their drive from Denver to Silverton, their LC200 threw a P2420.
Based on their experience, they suggested I replace the charcoal canister.

The next day on a trail, my permanent code went away. That was over 3 weeks ago and I've put over 2,500 miles on the truck, mostly driving it back across the country.

It can be frustrating especially if your state requires emission testing and connecting to the OBD port. I'm good for at least a year.

I'm tempted to buy a new charcoal canister especially with the Serra Toyota online parts sale still in effect. I'm not excited about dropping the LRA to access the canister and throwing $$$ on a new canister with no guarantee it will eliminate this code from coming back.

Watching this thread closely.

 

[gasman4u]

P2420 is the charcoal canister unfortunately from what I’ve read and experienced.

 

[mcmarshing]

Well that's the part that throws me off - I just replaced the (expensive) charcoal canister and both of the valves on top of the engine.
I've been slammed during the week, but I'll eventually get to doing the full troubleshooting procedure. It's so close to acceptable limits though that I feel like there's a partial obstruction wherever the atmospheric evap air is getting fed in from when the pump releases the vacuum for the leak test. Similar to an axle breather that has a little bit of dirt in it restricting air from flowing back into the axle when the gear oil cools.

 

[prharper]

P2420 is the charcoal canister unfortunately from what I’ve read and experienced.

Seems to be the consensus.
Given the good sale from Serra Toyota in progress, just ordered:

• Summary​

• Charcoal Canister Assembly
• Subtotal
  $622.74
• Shipping
  $118.54
• Tax
  $0.00
• Total Savings
  $418.37
  Shipping Discount
  $118.54
  SET 25% Off Promo
  $107.64
  Dealer Discount
  $192.19
• 
  
• Total
  $322.91
  
  

 

[gasman4u]

That’s the cheapest I’ve seen one of these!

 

[mcmarshing]

Update:
Got a P0441 for the first time since replacing the charcoal canister. OBD fusion just says "incorrect purge flow". Techstream just said this message:

Going to avoid clearing my DTC and see if it self clears (maybe calibrating?)

 

[prharper]

Update:
Got a P0441 for the first time since replacing the charcoal canister. OBD fusion just says "incorrect purge flow". Techstream just said this message:
View attachment 3707962Going to avoid clearing my DTC and see if it self clears (maybe calibrating?)

Good idea

 

[prharper]

I thought that I had left my P2420 code back in CO at LCDC in early Aug.
It came back this week and my charcoal canister order from Serra Toyota finally arrived as well. Coincidence?

Got two months of driving without the code. Emptied LRA tank 2/3 to fill up main tank that was running low. Started truck next morning and had the go visit dealer message.....

 

[gasman4u]

Weigh your new charcoal canister before you install it! Then compare with your old one.

 

[mcmarshing]

I'm still battling some intermittent P2420's and P0441's (No LRA tank, just factory). Now that it's cooling down a bit, I haven't had a code as often as I was during the summer, but still annoying.

I went ahead and just bought "Charcoal Filter Sub-Assembly" 77706-60040 (labeled as canister filter in photo 1 and 2) with the guess that it's clogged up and not allowing enough air to return into the system when the post-5hr-leak-check is conducted. Didn't see any specific instructions (yet) on the manual for how to replace it, but i'm assuming it's fairly accessible like the charcoal canister.

 

[mcmarshing]

Hoping to put this in this weekend and see what’s up with the old one.

 

[gasman4u]

View attachment 3746757
Hoping to put this in this weekend and see what’s up with the old one.

Good news: that’s a brand new paper filter assembly that’s part of the breather system (iirc) -“canister filter” per the diagram above.

Bad news: per some of the conversations I’ve had, it’s not REALLY needed for the system to function.

I am (un)fortunately getting a trial by fire on the EVAP system due to all the issues I’ve had. Check out your vcv valves on top of your engine. And if the 2420 keeps popping up, your charcoal canister may be toast.

 

[mcmarshing]

I may have forgotten to mention above but ive already replaced the charcoal canister, both VCV valves and gas cap.

 

[gasman4u]

I must’ve (highly likely) missed it. Start looking for condensation in those lines. If all those parts have been replaced, you should have resolved the codes by now imo.

Unless there’s an electrical/signaling issue.

 

[mcmarshing]

Well I replaced filter, and now the problem is worse haha. Use to be 50/50 on P2420 code on start up and 1 out of 10 times getting a P0441, now I get it 100% of the time after x2 cold starts, or mid drive. cracked open the old filter, some dust on the clean side but nothing crazy.

Looked at expanded codes too, I have a C1201 code related to ABS air inlet (Gotta check book to see).

While I was down there I did notice the wires that connect into the cannister were looking a little exposed, but at this point I think i’m gonna just hand the keys to the toyota dealership…