Doggone O2 Sensors/Cats!!! PO 440 , 441 & 446 (might NOT be sensors)
12-30-08, 12:45 AM
#16
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I was going to agree with it not being the cats or sensors as well . It does look like an evap line leaking somewhere. To trace it is the hard part.
I would start with buying a new cap as it is cheap and should be replaced every 6 years for my liking.
I would start with buying a new cap as it is cheap and should be replaced every 6 years for my liking.
12-30-08, 06:43 AM
#17
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Well I took it to the emissions this morning and the guy said it looks like I fixed the problem. HIs reader though couldn't scan the car b/c I haven't driven it enough for it to have any info to "read". So I have to drive it around and bring it back.
4play4dr, I posted pretty much everything u need to check. Your valve may not be working. The dealer can plug in a device to see if the valve is moving or not.
4play4dr, I posted pretty much everything u need to check. Your valve may not be working. The dealer can plug in a device to see if the valve is moving or not.
12-30-08, 11:23 AM
#18
I have a 99 GS400 with 189,000 miles. I got all 3 codes 2 months ago, and I have a number of issues. I traced the PO441 and PO446 down to a leaky purge valve under the hood. Mine was stuck open (which is the common fault when it goes out). Prices range from $50.00 to 120.00 depending on dealership. Anytime you set a PO441 or 446, you will also get a PO440 code to say that you have a malfunction in the evap system. The other codes narrow it down.
I also experienced a flood condition while filling the vehicle with gas. Raw fumes were going through the stuck open valve, and directly into into the intake manifold. When I started the car at the gas station, it stumbled and nearly died because it had too much fuel in the intake manifold.
Once I changed the purge valve all symptoms went away, but PO440 came back. It keeps coming back each time I reset the 1 code. I am beginning to suspect my charcoal canister is bad, and I will replace it after the first of the year when I check closer. It is expensive, and a pain to change because of where it is located. I have seen prices as high as $450.00 and as low as $211.00 on the web. I think I caused my canister to go bad by always overfilling my gas tank at the service station. That excess gas found its' way into the charcoal canister, and over the years the liquid ruined it. The canister is supposed to have fumes, but not liquid. My mistake. I'll never overfill my tank again.
If you change the canister make sure you change all associated hoses, because they are worn as well. They are available separately from the dealership. The valve in the canister should come with it.
I changed the gas cap, and that wasn't the problem. Since the PO441 and PO446 went away with the change of the purge valve, I assume both the purge valve and the tank valve are both opening and closing properly.
My PO440 code always comes back after about 1000 miles of driving. I have a vacuum leak smaller that .040, and it could definitely be that canister leaking on the body itself.
MONITORS
Let's talk about how your car checks itself while driving.
I have my own scanner, and I can see that my car is trying to correct itself. I go into the "MONITORS" section (which show that the vehicle is watching for things that could set a code).
ANYTIME you first reset the computer, (with a scanner, or by disconnecting the battery on some cars), if you immediately recheck the monitors section again, you will find that ALL the functions say NOT SET, or NOT READY. YOU have erased the history the computer had stored for your car.
No smog place in California will pass your vehicle even if the smog numbers are low enough to PASS the vehicle on performance. You must have 5 of the 9 perameters say "SET or READY". Things like MISFIRE, 02 sensors, Catalytic converter, Comprehensive, and EVAP. Only one or two days of driving is needed to set most of the monitors.
The car "cycles", or heats and cools each time you start out driving from cold and heat the coolant up to normal and cools down again. That counts as one cycle. The computer looks for a predetermined amount of cycles before it SETS the monitor and says READY. EVAP is the hardest code to "set". If the EVAP system is still leaking, or the purge valve fails to open forf a number of cycles, the check engine light comes back on and sets a fault code.
If you have codes 440, 441 or 446, the EVAP MONITOR will not set. That is my problem. Everything else sets fine and the car runs fine, but my very small vacuum leak takes 1000 miles of driving to leak enough to set the PO440 code. Then the cycle starts all over again.
Once long ago I mistakenly reset my computer just minutes before I took it in for smog certification. The vehicle passed emission testing with flying colors, but when the technician checked the monitors, all were "not ready". He would not pass my car until I drove for a few days to see what the computer was monitoring. This keeps people from resetting the codes on a problem car just before they sell it. The unsuspecting new owner does not know about the problems until after he takes delivery. In California that is illegal.
I hope this helps someone.
Now back to the car in question. I don't think that vehicle has 02 and catalytic converter problems. I still have my original parts, and my car is 10 years old. It runs great and I get excellent gas mileage. Don't trust that dealer.
My $.02
I also experienced a flood condition while filling the vehicle with gas. Raw fumes were going through the stuck open valve, and directly into into the intake manifold. When I started the car at the gas station, it stumbled and nearly died because it had too much fuel in the intake manifold.
Once I changed the purge valve all symptoms went away, but PO440 came back. It keeps coming back each time I reset the 1 code. I am beginning to suspect my charcoal canister is bad, and I will replace it after the first of the year when I check closer. It is expensive, and a pain to change because of where it is located. I have seen prices as high as $450.00 and as low as $211.00 on the web. I think I caused my canister to go bad by always overfilling my gas tank at the service station. That excess gas found its' way into the charcoal canister, and over the years the liquid ruined it. The canister is supposed to have fumes, but not liquid. My mistake. I'll never overfill my tank again.
If you change the canister make sure you change all associated hoses, because they are worn as well. They are available separately from the dealership. The valve in the canister should come with it.
I changed the gas cap, and that wasn't the problem. Since the PO441 and PO446 went away with the change of the purge valve, I assume both the purge valve and the tank valve are both opening and closing properly.
My PO440 code always comes back after about 1000 miles of driving. I have a vacuum leak smaller that .040, and it could definitely be that canister leaking on the body itself.
MONITORS
Let's talk about how your car checks itself while driving.
I have my own scanner, and I can see that my car is trying to correct itself. I go into the "MONITORS" section (which show that the vehicle is watching for things that could set a code).
ANYTIME you first reset the computer, (with a scanner, or by disconnecting the battery on some cars), if you immediately recheck the monitors section again, you will find that ALL the functions say NOT SET, or NOT READY. YOU have erased the history the computer had stored for your car.
No smog place in California will pass your vehicle even if the smog numbers are low enough to PASS the vehicle on performance. You must have 5 of the 9 perameters say "SET or READY". Things like MISFIRE, 02 sensors, Catalytic converter, Comprehensive, and EVAP. Only one or two days of driving is needed to set most of the monitors.
The car "cycles", or heats and cools each time you start out driving from cold and heat the coolant up to normal and cools down again. That counts as one cycle. The computer looks for a predetermined amount of cycles before it SETS the monitor and says READY. EVAP is the hardest code to "set". If the EVAP system is still leaking, or the purge valve fails to open forf a number of cycles, the check engine light comes back on and sets a fault code.
If you have codes 440, 441 or 446, the EVAP MONITOR will not set. That is my problem. Everything else sets fine and the car runs fine, but my very small vacuum leak takes 1000 miles of driving to leak enough to set the PO440 code. Then the cycle starts all over again.
Once long ago I mistakenly reset my computer just minutes before I took it in for smog certification. The vehicle passed emission testing with flying colors, but when the technician checked the monitors, all were "not ready". He would not pass my car until I drove for a few days to see what the computer was monitoring. This keeps people from resetting the codes on a problem car just before they sell it. The unsuspecting new owner does not know about the problems until after he takes delivery. In California that is illegal.
I hope this helps someone.
Now back to the car in question. I don't think that vehicle has 02 and catalytic converter problems. I still have my original parts, and my car is 10 years old. It runs great and I get excellent gas mileage. Don't trust that dealer.
My $.02
Last edited by gserep1; 12-30-08 at 12:12 PM.
12-30-08, 09:08 PM
#20
It is VERY easy to change it on a GS400.
1. First remove the black engine cover with the 4 hardware pieces (2 bolts 2 nuts).
2. Locate the purge valve on the top of the engine on the drivers side. It has two vacuum hoses on it, and an electrical connector that just snaps off. The entire valve is mounted to the engine by one screw ( I believe it is 12mm). If you see a vacuum line with a small green cap on it (the evap line), follow it up to the valve it connects to. THAT is the purge valve. The one line comes in, and the other line goes directly to a tube that connects into the top of the intake manifold. That is the vacuum source when the purge valve is open. The valve opens when the computer energizes the coil inside the valve. With no voltage on the valve, it should be closed and allow no air to go through it. Remove it to check it.
3. You can check it by either connecting a small vacuum pump to one port, or gently blowing on one of the two ports. The other end should have no air coming out. Most of these valves are stuck open when they go bad. Very few are stuck closed.
If it is stuck closed, the fuel tank never gets any vacuum, (and no purge), and you'll get a light for that too.
It does not stay on all the time normally while driving. The computer electrically energizes the coil for a few seconds and then shuts off again to measure the amount of vacuum in the fuel tank, if any.
Hope this helps!
1. First remove the black engine cover with the 4 hardware pieces (2 bolts 2 nuts).
2. Locate the purge valve on the top of the engine on the drivers side. It has two vacuum hoses on it, and an electrical connector that just snaps off. The entire valve is mounted to the engine by one screw ( I believe it is 12mm). If you see a vacuum line with a small green cap on it (the evap line), follow it up to the valve it connects to. THAT is the purge valve. The one line comes in, and the other line goes directly to a tube that connects into the top of the intake manifold. That is the vacuum source when the purge valve is open. The valve opens when the computer energizes the coil inside the valve. With no voltage on the valve, it should be closed and allow no air to go through it. Remove it to check it.
3. You can check it by either connecting a small vacuum pump to one port, or gently blowing on one of the two ports. The other end should have no air coming out. Most of these valves are stuck open when they go bad. Very few are stuck closed.
If it is stuck closed, the fuel tank never gets any vacuum, (and no purge), and you'll get a light for that too.
It does not stay on all the time normally while driving. The computer electrically energizes the coil for a few seconds and then shuts off again to measure the amount of vacuum in the fuel tank, if any.
Hope this helps!
12-30-08, 10:29 PM
#22
my p0440 diognosis.
- changed fuel cap, CEL P0440 comes back after about a week of regular driving.
- toyota scan tool, turned on the switch under the hood in the engine bay (turning it on and off made a clicking sound) so the switch was working.
- last possible thing is the charcoal canister. the part itself isnt cheap, but isnt crazy expensive, the labour in which to change it however is a lot. its located between the body and the transmission. so to reach it u have to lower the transmission.
- changed fuel cap, CEL P0440 comes back after about a week of regular driving.
- toyota scan tool, turned on the switch under the hood in the engine bay (turning it on and off made a clicking sound) so the switch was working.
- last possible thing is the charcoal canister. the part itself isnt cheap, but isnt crazy expensive, the labour in which to change it however is a lot. its located between the body and the transmission. so to reach it u have to lower the transmission.
12-30-08, 10:54 PM
#23
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You may be able to just buy the charcoal and refill the canister and reseal it also.
Charcoal is very similar to other applications using it such as aquarium filter tanks. Coconut shell carbon is highly recommended as the better ones for that as it absorbs contaminants as well as odors easily. So for an hour work and $15 you could repair the canister.
Charcoal is very similar to other applications using it such as aquarium filter tanks. Coconut shell carbon is highly recommended as the better ones for that as it absorbs contaminants as well as odors easily. So for an hour work and $15 you could repair the canister.
12-31-08, 08:24 AM
#24
1SICKLEX,
It is a pleasure to assist wherever I can. I've seen your posts forever, and never thought I would talk directly to you. I joined back in 2003 when I got my first 99 GS400 with 72,000 mles. It was Alpine Silver. That was the best car. Did my first timing belt when it hit 90,000 miles, and I've never looked back. I do all my work except alignments.
That car was destroyed on the Coronado Bridge in San Diego in 2004, so I had to find another one. I bought the Gold 99 GS400 from Arizona in the summer of 2004 with 59,000 miles on it. It was babied, and never has run as strong as the first car, (which was a BEAST stock. some cars are like that.)
I now have 189,000 miles on it, and it runs great. The idle is as smooth as silk, but just something about it that makes it different. I've done 2 timing belts on it, (and water pumps). This PO440 is the first and only check engine light concern I've had. I really think I need the charcoal canister. I'll do the work, but it doesn't look easy. I think I wrecked it by filling the gas up to the neck so many times.
After the holidays, I'll really look into diagnosing the system before I buy the charcoal canister. I want to check every hose and fitting for a VERY SMALL vacuum leak. It has to be small to take 1000 miles or more before triggering the light. I keep my scanner n the car, and I often hook it up to see if the EVAP monitor has set, and it never has. I'm still leaking a little bit, but I have to find out where.
Please keep in touch, and we'll talk again whenever you feel the need.
Jessie (aka gserep1) One day I'll have to pm you concerning my web name.
It is a pleasure to assist wherever I can. I've seen your posts forever, and never thought I would talk directly to you. I joined back in 2003 when I got my first 99 GS400 with 72,000 mles. It was Alpine Silver. That was the best car. Did my first timing belt when it hit 90,000 miles, and I've never looked back. I do all my work except alignments.
That car was destroyed on the Coronado Bridge in San Diego in 2004, so I had to find another one. I bought the Gold 99 GS400 from Arizona in the summer of 2004 with 59,000 miles on it. It was babied, and never has run as strong as the first car, (which was a BEAST stock. some cars are like that.)
I now have 189,000 miles on it, and it runs great. The idle is as smooth as silk, but just something about it that makes it different. I've done 2 timing belts on it, (and water pumps). This PO440 is the first and only check engine light concern I've had. I really think I need the charcoal canister. I'll do the work, but it doesn't look easy. I think I wrecked it by filling the gas up to the neck so many times.
After the holidays, I'll really look into diagnosing the system before I buy the charcoal canister. I want to check every hose and fitting for a VERY SMALL vacuum leak. It has to be small to take 1000 miles or more before triggering the light. I keep my scanner n the car, and I often hook it up to see if the EVAP monitor has set, and it never has. I'm still leaking a little bit, but I have to find out where.
Please keep in touch, and we'll talk again whenever you feel the need.
Jessie (aka gserep1) One day I'll have to pm you concerning my web name.
12-31-08, 10:11 AM
#25
Driver
Take it to the delaership and pay for a smoke test, then repair whatever is leaking.
the charcoal cannister is a sealed unit, dont open and try and repack it with charcoal, if you dont seal it properly you will have to redo the work again. just buy the part and replace it.
We replace the vent valve and charcoal cannister for that code(p0440) sometimes the cannister has a hairline crack in it that will cause this.
the charcoal cannister is a sealed unit, dont open and try and repack it with charcoal, if you dont seal it properly you will have to redo the work again. just buy the part and replace it.
We replace the vent valve and charcoal cannister for that code(p0440) sometimes the cannister has a hairline crack in it that will cause this.
12-31-08, 03:13 PM
#26
Lexus Champion
It is VERY easy to change it on a GS400.
1. First remove the black engine cover with the 4 hardware pieces (2 bolts 2 nuts).
2. Locate the purge valve on the top of the engine on the drivers side. It has two vacuum hoses on it, and an electrical connector that just snaps off. The entire valve is mounted to the engine by one screw ( I believe it is 12mm). If you see a vacuum line with a small green cap on it (the evap line), follow it up to the valve it connects to. THAT is the purge valve. The one line comes in, and the other line goes directly to a tube that connects into the top of the intake manifold. That is the vacuum source when the purge valve is open. The valve opens when the computer energizes the coil inside the valve. With no voltage on the valve, it should be closed and allow no air to go through it. Remove it to check it.
3. You can check it by either connecting a small vacuum pump to one port, or gently blowing on one of the two ports. The other end should have no air coming out. Most of these valves are stuck open when they go bad. Very few are stuck closed.
If it is stuck closed, the fuel tank never gets any vacuum, (and no purge), and you'll get a light for that too.
It does not stay on all the time normally while driving. The computer electrically energizes the coil for a few seconds and then shuts off again to measure the amount of vacuum in the fuel tank, if any.
Hope this helps!
1. First remove the black engine cover with the 4 hardware pieces (2 bolts 2 nuts).
2. Locate the purge valve on the top of the engine on the drivers side. It has two vacuum hoses on it, and an electrical connector that just snaps off. The entire valve is mounted to the engine by one screw ( I believe it is 12mm). If you see a vacuum line with a small green cap on it (the evap line), follow it up to the valve it connects to. THAT is the purge valve. The one line comes in, and the other line goes directly to a tube that connects into the top of the intake manifold. That is the vacuum source when the purge valve is open. The valve opens when the computer energizes the coil inside the valve. With no voltage on the valve, it should be closed and allow no air to go through it. Remove it to check it.
3. You can check it by either connecting a small vacuum pump to one port, or gently blowing on one of the two ports. The other end should have no air coming out. Most of these valves are stuck open when they go bad. Very few are stuck closed.
If it is stuck closed, the fuel tank never gets any vacuum, (and no purge), and you'll get a light for that too.
It does not stay on all the time normally while driving. The computer electrically energizes the coil for a few seconds and then shuts off again to measure the amount of vacuum in the fuel tank, if any.
Hope this helps!
01-01-09, 12:07 AM
#27
The purge valve works exactly the same way on the GS300. I just don't know EXACTLY where the valve is. I would suggest that you:
1. Raise hood and check for a hose coming from the rear of the car forward. This hose has the SMALL GREEN EVAP cap on it. The fumes from the charcoal canister come in on that line. Removing the green cap will reveal a schraeder valve like a tire valve stem. DO NOT pressurize that line. It onlytakes 1 psi maximum for saervice technicians to check the system. Extra pressure will damage the tank valve out back.
2. That line connects to the purge valve. The purge valve, as described earlier has an electric connection and two ports for fumes to go through it when commanded by the computer. The other line goes directly to the intake manifold for controlled burning when necessary. The computer also leans out the fuel injectors to prevent an overly rich mixture at the catalytic converter when the fumes are being burned. It has all been measured and calculated, so when smething goes wrong, the light has to come on to alert the driver.
The valve may or may not be the same part number as the GS400. I am not sure about that. I don't know anyone with a GS300, but if I did, I'd take a picture and post it. I do know that it should be very close to the vacuum source, which is the intake manifold.
When that valve sticks all the way open and you refuel the car, the fumes will almost flood the engine, and hard starting will be the result. If that valve stays closed, there will be pressure in the tank from the expanding gases, and there will be a "whooshing" sound when you take off the cap. This is especially true if the tank has been allowed to run down very low...(more fumes in the tank then).
Good luck and HAPPY NEW YEAR TO ALL!
1. Raise hood and check for a hose coming from the rear of the car forward. This hose has the SMALL GREEN EVAP cap on it. The fumes from the charcoal canister come in on that line. Removing the green cap will reveal a schraeder valve like a tire valve stem. DO NOT pressurize that line. It onlytakes 1 psi maximum for saervice technicians to check the system. Extra pressure will damage the tank valve out back.
2. That line connects to the purge valve. The purge valve, as described earlier has an electric connection and two ports for fumes to go through it when commanded by the computer. The other line goes directly to the intake manifold for controlled burning when necessary. The computer also leans out the fuel injectors to prevent an overly rich mixture at the catalytic converter when the fumes are being burned. It has all been measured and calculated, so when smething goes wrong, the light has to come on to alert the driver.
The valve may or may not be the same part number as the GS400. I am not sure about that. I don't know anyone with a GS300, but if I did, I'd take a picture and post it. I do know that it should be very close to the vacuum source, which is the intake manifold.
When that valve sticks all the way open and you refuel the car, the fumes will almost flood the engine, and hard starting will be the result. If that valve stays closed, there will be pressure in the tank from the expanding gases, and there will be a "whooshing" sound when you take off the cap. This is especially true if the tank has been allowed to run down very low...(more fumes in the tank then).
Good luck and HAPPY NEW YEAR TO ALL!
Last edited by gserep1; 01-01-09 at 12:11 AM.
01-15-09, 12:14 PM
#29
Guest
Posts: n/a
1SICKLEX,
It is a pleasure to assist wherever I can. I've seen your posts forever, and never thought I would talk directly to you. I joined back in 2003 when I got my first 99 GS400 with 72,000 mles. It was Alpine Silver. That was the best car. Did my first timing belt when it hit 90,000 miles, and I've never looked back. I do all my work except alignments.
That car was destroyed on the Coronado Bridge in San Diego in 2004, so I had to find another one. I bought the Gold 99 GS400 from Arizona in the summer of 2004 with 59,000 miles on it. It was babied, and never has run as strong as the first car, (which was a BEAST stock. some cars are like that.)
I now have 189,000 miles on it, and it runs great. The idle is as smooth as silk, but just something about it that makes it different. I've done 2 timing belts on it, (and water pumps). This PO440 is the first and only check engine light concern I've had. I really think I need the charcoal canister. I'll do the work, but it doesn't look easy. I think I wrecked it by filling the gas up to the neck so many times.
After the holidays, I'll really look into diagnosing the system before I buy the charcoal canister. I want to check every hose and fitting for a VERY SMALL vacuum leak. It has to be small to take 1000 miles or more before triggering the light. I keep my scanner n the car, and I often hook it up to see if the EVAP monitor has set, and it never has. I'm still leaking a little bit, but I have to find out where.
Please keep in touch, and we'll talk again whenever you feel the need.
Jessie (aka gserep1) One day I'll have to pm you concerning my web name.
It is a pleasure to assist wherever I can. I've seen your posts forever, and never thought I would talk directly to you. I joined back in 2003 when I got my first 99 GS400 with 72,000 mles. It was Alpine Silver. That was the best car. Did my first timing belt when it hit 90,000 miles, and I've never looked back. I do all my work except alignments.
That car was destroyed on the Coronado Bridge in San Diego in 2004, so I had to find another one. I bought the Gold 99 GS400 from Arizona in the summer of 2004 with 59,000 miles on it. It was babied, and never has run as strong as the first car, (which was a BEAST stock. some cars are like that.)
I now have 189,000 miles on it, and it runs great. The idle is as smooth as silk, but just something about it that makes it different. I've done 2 timing belts on it, (and water pumps). This PO440 is the first and only check engine light concern I've had. I really think I need the charcoal canister. I'll do the work, but it doesn't look easy. I think I wrecked it by filling the gas up to the neck so many times.
After the holidays, I'll really look into diagnosing the system before I buy the charcoal canister. I want to check every hose and fitting for a VERY SMALL vacuum leak. It has to be small to take 1000 miles or more before triggering the light. I keep my scanner n the car, and I often hook it up to see if the EVAP monitor has set, and it never has. I'm still leaking a little bit, but I have to find out where.
Please keep in touch, and we'll talk again whenever you feel the need.
Jessie (aka gserep1) One day I'll have to pm you concerning my web name.
Thanks for sharing your story.Update
So the light came back on after I went to the emissions place the 2nd time. So it couldn't scan.
I have a bud that works on cars so I went over to his "garage". He took out both sensors and cleaned them with some tool. He said the 1st one seems to be the one giving issues. No store in the area had a Lexus one so I was going to buy a universal one.The light went off for about a day and came back on.
WEIRDEST THING I notice a couple days ago the light went off on the way home from work. I figured it would go back on. Well the next day, it was off all day.
So I say "let me try her this morning" and the light was off, so I drove her around some and took her to the emissions place.
Lo and behold it passed
and the light is still off. Weird but I am not complaining!
