I am doomed!!! - P0133,P0420,P0440 ,P0441,P0446

Hi All,
You folks are doing a great job as always!!
I took my Corolla 2002 (108000 miles) to 2 mechanics yesterday , since the check engine lights have been on since 2 months. I had purchased this car 3 months before and the Firestone mechanic said its safe to buy the car and has no problems. I am scared after seeing these details below

Please advice what are the actions that I can take up and what are the critical ones. Are all the items need to be done?

Thanks,
Sunny

Check with the dealer, all manufacturers has a warranty that exceed the one on your car for emissions. Do not quote me, but I think is 10 years or so. Call the dealer and ask. You might get a freebie or... partial freebie.

Take the car back to who sold it to you. If you sell a car it has to be able to pass a smog test...... it's the law!!

don,t trust pepboys,goodyear,firestone,etc.,etc. find a local honest mechanic that knows toyota,s. ask friends or family to rewcommend one. there is very little chance that a 2002 corolla with 108,000 miles needs all those parts replaced.

I don't think your doomed, it doesn't sound like that big of a deal to me. If the o2 sensor was replaced before, did your friend replace the correct one? Believe it or not, not everyone knows how to locate bank 1, sensor 1.
Now the cat. code: did you look on the site for the numerous posts about cheap cats and recurring 0420? If your friend was trying to sell the car, I don't think he'd spend very much on a cat. A very cheap cat can cause a recurring 0420. Check the site.
Third, the simplest EVAP problem isn't easy to diagnose because the EVAP system is under the vehicle and can set numerous codes. But it'snot rocket science. Try the first two problems yourself and then consider taking it to a shop for the EVAP code if you feel it's over your head.

Hi there,
8 yr toyota mechanic here, the o2 code is likely to mean you need a new o2. the cat code is likely to mean you need a new cat. agreed that if it was replaced with a cheap aftermarket it likely wont last or perform how computer expects. start with just the o2-- you might get lucky.
evap codes. if you're really lucky you just left your gas cap loose. may need a canister. however, most likely a bypass VSV located on the canister. they always go bad. don't get it mixed up with the other VSV's not on the canister. sounds like they wanted to replace every evap component-- clear sign they don't understand system.

change your own air filter
throttle body cleaning not a bad idea if carboned up but not necessary for code fixing.
MAF cleaning unnecessary unless getting lean codes (ex p0171)
Idle cleaning unnecessary and i doubt they would actually do anything
step pro fuel-- eh, if you got extra money. won't actually fix anything more of a preventative maint thing
air valve? don't know what they mean
good luck

Well, it's not going to be a gas cap. A gas cap leaking won't cause a circuit malfunction.

Actually, it could be a loose gas cap. by circuit they mean the evap plumbing, not an electical curcuit. Curcuit is a generic term, albeit most commonly refering to electrical systems but not limited to.

If you were right, I would believe you. Circuit does not refer to plumbing, only wiring.

check out the toyota repair manual. step 2 in the trouble tree is to check the gas cap. check out the list of dtc detection list. they speak of no "continuity" between the press sensor, fuel tank, and canister, which IS refering to the "plumbing." however it may also be an elecrical issue too.
fun debate!

Im sorry but vent control circuit malfunction doesn't refer to plumbing. If you want to check it out, it's generic obd ii code. A vent cap won't cause a vent circuit malfunction, it's impossible. Never happen. Ever. If there was only one code referring to "small evap leak" or "large Evap leak" then yeah, checking the gas cap would be a good start, but when you have 3 codes two of which relate to "control of the EVAP system" and the third is the above code, any tech worth his salt won't go for a cap or ask anyone to check a cap. It a non issue. It's a waste of time.
To be clear, I think the pep boys technical readout is a joke and there's no way Id replace all the components they said were bad without a second opinion.
Im done.

copy and pasted right out of the toyota maual.

P0440
P0442
After cold starting and when generating certain swift pressure
value in fuel tank enabling not to hold that value (2 trip detection
logic)

truouble areas for p0440 and p0442

 Hose or tube cracked, hole, damaged or loose seal ((3) in
Fig. 1)
 Fuel tank cap incorrectly installed
 Fuel tank cap cracked or damaged
Vacuum hose cracked, holed, blocked, damaged or disconnected
((1) or (2) in Fig. 1)
 Fuel tank cracked, holed or damaged
 Charcoal canister cracked, holed or damaged
 Open or short in vapor pressure sensor circuit
Vapor pressure sensor
 Fuel tank over fill check valve cracked or damaged
ECM


P0441
Pressure in charcoal canister and fuel tank does not drop during
purge control (2 trip detection logic)

P0446
When VSV for pressure switching valve is ON, ECM judges
that there is no continuity between vapor pressure sensor , fuel
tank and charcoal canister (2 trip detection logic)
When VSV for pressure switching valve is turned OFF, pressure
in fuel tank is maintained at atmospheric pressure (2 trip
detection logic)
When VSV for CCV is ON, pressure in charcoal canister and
fuel tank is maintained st atmospheric pressure (2 trip detection
logic)

trouble areas for p0446 and p0441

Vacuum hose cracks, holed blocked, damaged or disconnected
((1), (2),(3), (4), (5), (6), (7), (8), (9), (10) and (11) in
Fig. 1)
 Fuel tank cap incorrectly installed
 Fuel tank cap cracked or damaged
 Open or short in vapor pressure sensor circuit
Vapor pressure sensor
 Open or short in VSV circuit for EVAP
 VSV for EVAP
 Open or short in VSV circuit for CCV
 VSV for CCV
 Open or short in VSV circuit for pressure switching valve
 VSV for pressure switching valve
 Fuel tank cracked, holed or damaged
 Charcoal canister cracked, holed or damaged
 Fuel tank over fill check valve cracked damaged
ECM

unfortunately i cannot paste the diagram which would further back up what i am saying

sorry but it is true that the cap can throw all 3 codes. as stated before unlikely in this guys case but theoretically it can... and does, i have had tons of brand new cars come in with these codes due to loose gas cap.
true newer models are a little more sophisticated and more likely to throw small or large leak detection codes with a loose gas cap. this model could throw a small leak code. it doesn't have a large leak code detection capability.

now we are both done
still a fun debate!

Hi,

I'm not sure if you guys are still monitoring this thread, but I have a 2005 Toyota Sienna which came up with the codes 0440, 0441, and 0446 last week. I'm not a mechanic and I didn't have the codes read until just today. In between the time that the codes came up and when I had them read today, I filled the gas and I think that my wife had not put the gas cap all the way on the last time the car was filled. As soon as the dealership told me that it might just be a simple gas cap issue, I told them to just reset the code and then we'd see if it came back up.

Flash forward to tonight. I picked up the car from the dealership and the lights were still on! So, my question is -- is it possible that they just forgot to reset the codes? If they *did* reset the codes, would they come back on almost immediately if there was a real problem with the EVAP system or would you need to drive the car for a while before they come back on?

I would like to reset the codes again myself and see what happens. Can I do that by removing the negative battery cable for 30 seconds?

They just didn't clear the codes. those codes wouldn't return that quick. Clear them yourself or take it to autozone have them pull and clear the codes. you can disconnect the battery but sometimes an idle quality issue will arise if your throttle body has carbon build up in.
good luck!

Thanks, I actually went to AutoZone tonight, but didn't have time to wait around for them. I'll go back tomorrow to get it reset. I just feel like an ass that I paid the dealership $49 to read the code, and then they didn't even reset it!!