P0446 EVAP Control System Vent Control Circuit Malfunction
CL Community Team
Joined: Apr 2007
Posts: 12,397
Likes: 453
From: GA
Back from hibernation…P0442 EVAP LEAK RX330
Most recently a P0442 has been popping up and it is getting more frequent. After reset, it comes back quicker now. I used to go driving for days and it would eventually pop up. Time to investigate where the leak is coming from. My Evap rubber tubes are not cracked, one or 2 of them I replaced a couple of years ago. They tend to degrade and crack over time. Bought me a couple of feet of the tube at Oreilly’s.
Fast forward to most recently, the CEL keeps on coming back. As the RX330 is a daily driver, it is annoying to see the CEL on. I happen to have a Scangage and I put it on so I can clear CELs on demand. On the way to work today, it popped up again (just cleared it last night).
So based on other member’s experience what is likely the root cause?
1. Evap Tubes leaking – I do not see old worn out tubes
2. Gas Cap – I will check on this tonight
3. ??
Help appreciated…thanks…
Most recently a P0442 has been popping up and it is getting more frequent. After reset, it comes back quicker now. I used to go driving for days and it would eventually pop up. Time to investigate where the leak is coming from. My Evap rubber tubes are not cracked, one or 2 of them I replaced a couple of years ago. They tend to degrade and crack over time. Bought me a couple of feet of the tube at Oreilly’s.
Fast forward to most recently, the CEL keeps on coming back. As the RX330 is a daily driver, it is annoying to see the CEL on. I happen to have a Scangage and I put it on so I can clear CELs on demand. On the way to work today, it popped up again (just cleared it last night).
So based on other member’s experience what is likely the root cause?
1. Evap Tubes leaking – I do not see old worn out tubes
2. Gas Cap – I will check on this tonight
3. ??
Help appreciated…thanks…
Lexus Champion
Joined: Apr 2019
Posts: 11,126
Likes: 1,560
From: FL
Back from hibernation…P0442 EVAP LEAK RX330
Most recently a P0442 has been popping up and it is getting more frequent. After reset, it comes back quicker now. I used to go driving for days and it would eventually pop up. Time to investigate where the leak is coming from. My Evap rubber tubes are not cracked, one or 2 of them I replaced a couple of years ago. They tend to degrade and crack over time. Bought me a couple of feet of the tube at Oreilly’s.
Fast forward to most recently, the CEL keeps on coming back. As the RX330 is a daily driver, it is annoying to see the CEL on. I happen to have a Scangage and I put it on so I can clear CELs on demand. On the way to work today, it popped up again (just cleared it last night).
So based on other member’s experience what is likely the root cause?
1. Evap Tubes leaking – I do not see old worn out tubes
2. Gas Cap – I will check on this tonight
3. ??
Help appreciated…thanks…
Most recently a P0442 has been popping up and it is getting more frequent. After reset, it comes back quicker now. I used to go driving for days and it would eventually pop up. Time to investigate where the leak is coming from. My Evap rubber tubes are not cracked, one or 2 of them I replaced a couple of years ago. They tend to degrade and crack over time. Bought me a couple of feet of the tube at Oreilly’s.
Fast forward to most recently, the CEL keeps on coming back. As the RX330 is a daily driver, it is annoying to see the CEL on. I happen to have a Scangage and I put it on so I can clear CELs on demand. On the way to work today, it popped up again (just cleared it last night).
So based on other member’s experience what is likely the root cause?
1. Evap Tubes leaking – I do not see old worn out tubes
2. Gas Cap – I will check on this tonight
3. ??
Help appreciated…thanks…
What is your year/model/current mileage?
Also, if you clear the CEL and start your car cold does the CEL come on instantly or does it take approx 5 mins or so?
Lexus Champion
Joined: Apr 2019
Posts: 11,126
Likes: 1,560
From: FL
For anyone hunting down EVAP leaks/codes you can maybe rule out anything up front at the engine by checking these valves for proper operation
with an easy test.
When the car first starts up cold and the big vacuum line on the engine going back towards the gas tank is clamped off- there should be no vacuum measured
here from the valve- this valve should be closed and tight(not leaking).
Once the car warms up to operating temp the VSV will switch on/off and purge the vapors from the back of the car as
shown on the gauge with vacuum pulsing.
I always keep a vacuum T(plugged) on this vacuum line and by the way I really like my Harbor Freight gauge and it feels like quality.
PS- If theCheck Engine Light takes a long time to come on I would look toward the rear of the car at the evap components but maybe others have ideas too...
Last edited by Margate330; Feb 6, 2020 at 07:52 PM.
CL Community Team
Joined: Apr 2007
Posts: 12,397
Likes: 453
From: GA
I filled up gas this morning and I made sure I closed that Gas Cap tight. I was guilty, I kind of twisted it and heard a click, then I realized, maybe it was the issue. So I went back and tightened it. The CEL went on this morning and I had 58 miles on the meter. I cleared it with my scangage and let's see...thanks for all your suggestions!
CL Community Team
Joined: Apr 2007
Posts: 12,397
Likes: 453
From: GA
I bit the bullet and purchased a new Gas Cap for the RX330 made bay Gates.
And while looking through my drawers this weekend, I saw a brand new Toyota Gas Cap...!!!!
So apparently this has been an issue a long time ago (but it could have been for another car issue, I have 3 Toyota cars – are these one style generic caps?). The RX330 is the one that’s showing the P0442.
And while looking through my drawers this weekend, I saw a brand new Toyota Gas Cap...!!!!
So apparently this has been an issue a long time ago (but it could have been for another car issue, I have 3 Toyota cars – are these one style generic caps?). The RX330 is the one that’s showing the P0442.
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3rd Gear
Joined: May 2023
Posts: 3
Likes: 0
From: TX
Hi,
P0446="EVAPORATIVE EMISSION CONTROL SYSTEM VENT CONTROL CIRCUIT" (Open or close malfunction in CCV - 2 trip detection logic).
Quote. "MONITOR DESCRIPTION. The ECM tests the Evaporative Emissions (EVAP) system using the fuel tank pressure sensor, Canister Close Valve (CCV), and EVAP VSV. The ECM closes the EVAP system and creates negative pressure (vacuum) into it. The ECM then monitors the internal pressure using the fuel tank pressure sensor..."
Toyota has TSB EG003-03* ("M.I.L. "ON" DTC P0441, P0442 AND/OR P0446") and TSB EG008-04R ("REPAIR MANUAL SUPPLEMENT... DTCP0446...") for RX330 a '04.
HTH,
-------------------------------------------
*"...The EVAP Purge VSV has been improved to correct the M.I.L. “ON” condition."
* Applicable Warranty: This repair is covered under the Lexus Comprehensive Warranty. This warranty is in effect for 48 months or 50,000 miles, whichever occurs first, from the vehicle’s
in-service date.
P0446="EVAPORATIVE EMISSION CONTROL SYSTEM VENT CONTROL CIRCUIT" (Open or close malfunction in CCV - 2 trip detection logic).
Quote. "MONITOR DESCRIPTION. The ECM tests the Evaporative Emissions (EVAP) system using the fuel tank pressure sensor, Canister Close Valve (CCV), and EVAP VSV. The ECM closes the EVAP system and creates negative pressure (vacuum) into it. The ECM then monitors the internal pressure using the fuel tank pressure sensor..."
Toyota has TSB EG003-03* ("M.I.L. "ON" DTC P0441, P0442 AND/OR P0446") and TSB EG008-04R ("REPAIR MANUAL SUPPLEMENT... DTCP0446...") for RX330 a '04.
HTH,
-------------------------------------------
*"...The EVAP Purge VSV has been improved to correct the M.I.L. “ON” condition."
* Applicable Warranty: This repair is covered under the Lexus Comprehensive Warranty. This warranty is in effect for 48 months or 50,000 miles, whichever occurs first, from the vehicle’s
in-service date.
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