check engine code PO 440 PO 446
#16
I had this issue for almost a year in my 1999 RX300. At one point I replaced the gas cap with an aftermarket one. It didn't help the code, but it did create a new problem where the gas cap was extremely hard to remove on a low tank. I replaced it with a real Toyota cap.
I'm due for an inspection so I finally got around to testing this system. The VSV's on top of the engine tested fine as did the ones on top of the charcoal canister. I tested the canister according to the testing procedure and it failed.
The canister part number was a pain to figure out.
The original was 77740-48010.
There was an April 1999 TSB EG001-99 that said it was replaced by 77740-48030. I couldn't find that part.
Two other sites that looked up the part by VIN number said it was now 77740-48011. I was able to find a new one of those on ebay for $400. Installed it a few days ago, looks good so far.
I'm due for an inspection so I finally got around to testing this system. The VSV's on top of the engine tested fine as did the ones on top of the charcoal canister. I tested the canister according to the testing procedure and it failed.
The canister part number was a pain to figure out.
The original was 77740-48010.
There was an April 1999 TSB EG001-99 that said it was replaced by 77740-48030. I couldn't find that part.
Two other sites that looked up the part by VIN number said it was now 77740-48011. I was able to find a new one of those on ebay for $400. Installed it a few days ago, looks good so far.
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chenxingha (09-21-22)
#17
Just an fyi:
Yep, for me it was the cap at ~40k miles. So I'm guessing that this is an age defect thing and not a mileage thing (like the O2 sensors seem to fail based on age and not milage). I replaced the cap with a Gates brand cap: P/N: GAT 31612 . All of $6.13 US, delivered.
Btw, I tested the defective cap with a very special tool: I put my mouth over it and sucked. No vacuum release whatsoever. The I did the same test on new cap, with same proprietary tool: Vacuum release at about 12 lbs vacuum (ie. almost as hard as I could suck on it). Fyi, I tested my proprietary tester with a real vacuum gauge to see how hard I could suck: I'm a 15 lb sucker!
Regards . . .
P.S. No comments form the peanut gallery please ;-)
P.S. Thanks maxSteel for that canister research workout. Hope I don't need to go hunting for one of those.
Yep, for me it was the cap at ~40k miles. So I'm guessing that this is an age defect thing and not a mileage thing (like the O2 sensors seem to fail based on age and not milage). I replaced the cap with a Gates brand cap: P/N: GAT 31612 . All of $6.13 US, delivered.
Btw, I tested the defective cap with a very special tool: I put my mouth over it and sucked. No vacuum release whatsoever. The I did the same test on new cap, with same proprietary tool: Vacuum release at about 12 lbs vacuum (ie. almost as hard as I could suck on it). Fyi, I tested my proprietary tester with a real vacuum gauge to see how hard I could suck: I'm a 15 lb sucker!
Regards . . .
P.S. No comments form the peanut gallery please ;-)
P.S. Thanks maxSteel for that canister research workout. Hope I don't need to go hunting for one of those.
Last edited by Brcobrem; 06-02-17 at 01:05 PM.
The following 2 users liked this post by Brcobrem:
chenxingha (09-21-22),
fred9xx (08-21-22)
#18
On a related note and if interested, I posted one fix for the P0440 code here:
https://www.clublexus.com/forums/rx-...l#post10084024
Regards . . .
https://www.clublexus.com/forums/rx-...l#post10084024
Regards . . .
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chenxingha (09-21-22)
#19
Your pdf shows how to test without the dealer service tool using a vacuum and pressure gauge/meter. Search eBay for "evap port connector adapter" (no quotes) for the evap port adapter.
Regards . . .
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chenxingha (09-21-22)
#20
I had the engine cover off my 2000 RX300 and took a couple pics :
1. Overhead of engine plumbing (without trim cover):
2. Very Close Up of Evap VSV (blue) and AICS VSV's (orange). Please let me know if I mis-identified the parts:
3. Close Up of Evap plumbing - Top right of engine:
4. Close Up of Evap plumbing - Top center of engine:
5. Vacuum Tank as seen from ground looking up: I'm including this here only because I can't find the thread where I was asking where the vacuum tank was. I found it when I had to remove the cover under the engine when I dropped my hex key down in there (duh). Btw, on the top of the engine I was able to disconnect the hoses labeled #1 and #2 that go down to this tank and give it a quick human vacuum meter test (ie. the finger plug and suck test). No leaks here for me this time:
6. Valve on firewall side of the Air Cleaner Case: This appears to open/close the fresh air tube that goes back to the Evap unit under the rear end. I can't seems to find a reference to this valve. Anyone know what it's called or where it shows in that under vacuum line sticker under the hood?
I look forward to and appreciate any comments and/or corrections.
Regards . . .
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chenxingha (09-21-22)
#21
Oh yea, I forgot to mention: Why all the big fuss about a P0440 again? After 130 miles it's back again. That's why I ordered the adapter/connector for the Evap Port. When the wind dies down here some day this week, this time I'm going to smoke test, and if need be, run the vacuum and pressure tests on that port (as outlined in Tammy's pdf).
Regards . . .
Regards . . .
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chenxingha (09-21-22)
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chenxingha (09-21-22)
#23
Intermediate
Very much appreciate if you could mark the hose that you pointed to. I have not been able to find loose hoses near and around the air filter box - I could be missing somethings here.
#24
This is mine:
1999 RX300 air box hose
1999 RX300 air box hose
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chenxingha (09-21-22)
#25
Intermediate
Hi maxSteel:
Thanks for the direction. Here are what look like on my wife's 2000 RX300 behind the air box:
There is a solenoid (?) switch on the hose coming out of the airbox. The hose looks in good shape and it goes to a metal line (in the second photo); no loose ends that I can see.
Thanks for the direction. Here are what look like on my wife's 2000 RX300 behind the air box:
There is a solenoid (?) switch on the hose coming out of the airbox. The hose looks in good shape and it goes to a metal line (in the second photo); no loose ends that I can see.
#26
Can anyone else weigh in on the mystery solenoid on the air box?
It would make sense if it was the "Canister Close Valve" that BillJoeBob and Brcobrem were asking about.
I've got an MY2000 with that valve that keeps throwing codes, and I can't find it in any of the parts diagrams.
Is there a better place to reference parts diagrams?
Air Cleaner
https://parts.lexus.com/a/Lexus_2000...1410-1703.html
Vacuum Piping
https://parts.lexus.com/a/Lexus_2000...1410-1708.html
Fuel Tank
https://parts.lexus.com/a/Lexus_2000...1410-7701.html
It would make sense if it was the "Canister Close Valve" that BillJoeBob and Brcobrem were asking about.
I've got an MY2000 with that valve that keeps throwing codes, and I can't find it in any of the parts diagrams.
Is there a better place to reference parts diagrams?
Air Cleaner
https://parts.lexus.com/a/Lexus_2000...1410-1703.html
Vacuum Piping
https://parts.lexus.com/a/Lexus_2000...1410-1708.html
Fuel Tank
https://parts.lexus.com/a/Lexus_2000...1410-7701.html
The following 2 users liked this post by CSwain:
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#27
I was wrong. It's in the Air Cleaner Diagram, but there's not a row for it in the parts table.
The part number for this "Valve, Vacuum Switch" is 90910-12227.
https://parts.lexus.com/p/69376526/90910-12227.html
The part number for this "Valve, Vacuum Switch" is 90910-12227.
https://parts.lexus.com/p/69376526/90910-12227.html
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chenxingha (09-21-22)
#28
Intermediate
I have struggled to locate EVP leak(s) due to code P0440 over several weekends and I almost lost patience with it. For some reason (I decided to have a fresh start and pulled out the EFI fuse to clear the CEL light and then drove the car until ECL came back again. This time, the code reader gave THREE codes, which are P0440 (Evaporative Emission System), P0441 (Evaporative Emission System Incorrect Purge Flow) and P0446 (Evaporative Emission System Vent Control Circuit), in that order:
It seems to me that, from the words in each code, P0446 appears pointing to the culprit. But what does "Vent Control Circuit" points to? A solenoid valve? Which one?
Please advise.
It seems to me that, from the words in each code, P0446 appears pointing to the culprit. But what does "Vent Control Circuit" points to? A solenoid valve? Which one?
Please advise.
#29
We know those three codes can happen when the hose is disconnected from the air box.
You've said the hose looks connected. What about the other end? Have you checked for leaks along the way? If you follow the dotted lines it looks like it is marked "air inlet line".
Have you tested the various VSV's?
Did you do the canister diagnostic?
You've said the hose looks connected. What about the other end? Have you checked for leaks along the way? If you follow the dotted lines it looks like it is marked "air inlet line".
Have you tested the various VSV's?
Did you do the canister diagnostic?
Last edited by maxSteel; 09-21-22 at 02:44 PM.
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chenxingha (09-24-22)
#30
Intermediate
Hi maxSteel:
Thanks for the insightful instructions.
I have not done the Canister diagnostics just yet - partly because body aches have crept up my back (difficult to bend down) and partly because I did not have a step-by-step easy-to-complex "road map" and partly because I am still studying the use of the GREEN EVAP Service Port - trying to figure out what parts/tools are needed in order to connect a vacuum meter with it.
In the photo of your Post #24 the hose to the air box is a straight-through (on your 1999 model) and mine (2000 model) appears to have a CCV (Post #25) which matches in the schematic drawing. What should I look for before and after the CCV?
Many thanks.
Thanks for the insightful instructions.
I have not done the Canister diagnostics just yet - partly because body aches have crept up my back (difficult to bend down) and partly because I did not have a step-by-step easy-to-complex "road map" and partly because I am still studying the use of the GREEN EVAP Service Port - trying to figure out what parts/tools are needed in order to connect a vacuum meter with it.
In the photo of your Post #24 the hose to the air box is a straight-through (on your 1999 model) and mine (2000 model) appears to have a CCV (Post #25) which matches in the schematic drawing. What should I look for before and after the CCV?
Many thanks.