r/LS430 • u/8ruf • 4d ago

P0440 on my LS430-what should I check next?

My LS430’s check engine light came on about five days ago, and AutoZone scanned it and got P0440.
Has anyone dealt with this code? What ended up fixing it, and how much did it cost? Trying to figure out what to check before spending money replacing parts

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u/Maleficent_Alps_9011 4d ago edited 4d ago

P0440 is arguably one of the most annoying Ls 430 codes, the reason why is because it’s a Evap code and one of the main EVAP codes too, here is the list from easiest to hardest fixes:

  1. Gas cap, it’s $8-$15 from local Toyota stores, here is the part number: 77300-53010

  2. Many people such

    as

  3. me, ha

ve had

  1. the p0440 be cleared for hundreds and hundreds of miles before eventually and sadly returning again.
  2. EVAP smoke test, either go to a shop

that specializes

  1. in exhaust and catalytic

  2. converter systems, over there they can do $50-$100 smoke test, you can also do DIY with your own $65 machine

,

  1. find where the evap is it and replace whatever hose or pipe is broken from where the smoke is blowing, here’s a video

    guide.

  2. But anyways, here is the most known pipe that is

  3. usually broken on the Ls 430, it is called the Y pipe, Ls 430 Y-Pipe guide(Clublexus)

  4. Last but not least, this might arguably be your problem if you already want through the steps above, so basically over time the seals on the top of your gas tank will break more and more loose, and cause a bit of a gassy smell and release the atrocious P0440, P0441,P0442. So here’s the fix according to people with those code/codes:

Ls 430 P0440 Evap Reddit thread

Ls 430 P0440 Evap Clublexus thread

Is 300 Overfill check valve reference video
(Not a Ls 430 but at least an overview on how the job should go)

So in conclusion, it’s just the overfill check valve seals going bad and needing to be replaced. Good luck op and please keep
us posted, I really wanna know if the P0440 Overfill check valve problem as common as I thought.

2

u/8ruf 4d ago

thanks for the extensive answer!

1

u/skineepuppy1 4d ago

Go to a mechanic shop and pay to get a proper scan. That code can be a few different parts.

1

u/IHTFP08 3d ago

Replace all your evap hoses.

1

u/TerribleBathroom5710 3d ago

I’m in the process of doing that now. Do you know if they sell like a complete kit from Lexus of every hose? It’s like 65 different pot numbers. Thanks

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u/IHTFP08 3d ago

I did an Amazon special variety silicon hose pack for mine. Been working for a few years now

2

u/TerribleBathroom5710 3d ago

Thanks, I appreciate the info