P0446 and P0505

[azncapcom]

Just read and got these codes. Cleared and then the P0505 came back instantly. Does anyone have experience with these 2 codes? its a 2000 LE model.

[Dukeie]

P0505 is a Idle Control System Malfunction

A code P0446 could mean one or more of the following has happened:

Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM

Possible Solutions

With a P0446 OBD-II trouble code, here are some things to try:

Replace Vent valve
Repair open, short, or resistance problem in control circuit
Repair open, or short, or resistance problem in power circuit
Replace PCM

[fishexpo101]

Those are fairly common - especially the P0446 on the 8th gen Corolla. Should be quite a bit of info on this forum alone on those particular codes.

P0505 - Idle Control System Malfunction
P0446 - Emission Control System Vent Control Circuit Malfunction

The P0446 CEL, could be a number of things - anything from a bad VSV or CCV valve malfunction, leaky vacuum lines, or power/connector issue to those valves by the vapor canister. In some cases, it could mean the vapor canister is bad. I'd say about 90%-95% of the time, it is a clogged vent tube, leaky vacuum hose, and/or bad VSV/CCV (Vacuum Switching Valve/Canister Closed Valve) - the rest could be ECM, electrical, or vapor canister related. Most shops (more than 80%) will blame the vapor canister - not surprising, as that is one of the more expensive pieces down there. Have a "smoke" test down on the car - see if they can find any leaks. Just from the number of possible issues down there, IMO, well worth the $85 or so diagnostic charge to check it out. Once they pinpoint it for you, then you can replace that component yourself.

For the P0505 - could be an electric issue or the throttle body needing a good cleaning. There is an electrical test that can be done to verify if the IAC (Idle-Air Control) valve is functioning correctly. The IAC is located on the throttlebody itself. You could run a DIY test by observing the valve actuation while running it through a series of ECT sensor connection/disconnect with cycling the ignition. Or a Toyota tech can command the unit with a handheld diagnostic tool. It is possible that a bad IAC could be causing the P0446 code, though that is fairly remote.

[Crowbar911]

azn.

Judging from your other thread, I would say that this may go along with you feeling sick. If your evap system is throwing off fumes of some sort, and its being sucked in by the cowl thats on the bottom of the windshield, it would be entering the cabin.

Fish may be able to explain it better.

[teppista881]

In case you hadn't checked, make sure you don't have any disconnected hoses anywhere.

[azncapcom]

Originally Posted by fishexpo101

Those are fairly common - especially the P0446 on the 8th gen Corolla. Should be quite a bit of info on this forum alone on those particular codes.

P0505 - Idle Control System Malfunction
P0446 - Emission Control System Vent Control Circuit Malfunction

The P0446 CEL, could be a number of things - anything from a bad VSV or CCV valve malfunction, leaky vacuum lines, or power/connector issue to those valves by the vapor canister. In some cases, it could mean the vapor canister is bad. I'd say about 90%-95% of the time, it is a clogged vent tube, leaky vacuum hose, and/or bad VSV/CCV (Vacuum Switching Valve/Canister Closed Valve) - the rest could be ECM, electrical, or vapor canister related. Most shops (more than 80%) will blame the vapor canister - not surprising, as that is one of the more expensive pieces down there. Have a "smoke" test down on the car - see if they can find any leaks. Just from the number of possible issues down there, IMO, well worth the $85 or so diagnostic charge to check it out. Once they pinpoint it for you, then you can replace that component yourself.

For the P0505 - could be an electric issue or the throttle body needing a good cleaning. There is an electrical test that can be done to verify if the IAC (Idle-Air Control) valve is functioning correctly. The IAC is located on the throttlebody itself. You could run a DIY test by observing the valve actuation while running it through a series of ECT sensor connection/disconnect with cycling the ignition. Or a Toyota tech can command the unit with a handheld diagnostic tool. It is possible that a bad IAC could be causing the P0446 code, though that is fairly remote.

All this info is pretty hard to observe for me as im not very mechanically inclined... would this be expensive to fix if i brought it to the mechanic? if its not part extensive and not too hard on the labour that i can learn through a few hours reading on the internet, then please let me know where i can find out more info for DIY dummies. thanks

oh yeah the car also reported very HIGH CO% during the emissions test if that may help pinpoint a problem?

[fishexpo101]

High CO means an excessive rich air/fuel mix (too much fuel, not enough air). That could point at a number of issues.

Would help to know a little about the history of the car, mileage, age, how does it run in general, does it consume any oil between oil changes, what motor oil you run, what major maintenance has been done, etc.

Much of your posts - seem to point at a comprehensive tuneup fixing most of those issues. Expense - depends on what they find and how they diagnose the problem. If the mechanic is not familar with Toyota or family with this particular engine - they may opt for parts swapping for diagnosing the issues you are having. Generally this can get very expensive - as the emissions components are fairly expensive and labor is even higher, basically you are paying they to guess at the problem.

At the very least, get a diagnostic of the problem at hand, they'll report what they find, but you are not obligated to do the work there. Once you findout what the problem is - might be able to see if you can do it yourself. Most of the work in not diffucult to do - but does take some familiarity with the workings of the EVAP system and throttlebody. Some parts can be quite expensive to replace, but you generally find that it is the little bits that are causing the problems (damaged or missing hose, corroded connector, etc.).

[azncapcom]

Originally Posted by fishexpo101

High CO means an excessive rich air/fuel mix (too much fuel, not enough air). That could point at a number of issues.

Would help to know a little about the history of the car, mileage, age, how does it run in general, does it consume any oil between oil changes, what motor oil you run, what major maintenance has been done, etc.

Much of your posts - seem to point at a comprehensive tuneup fixing most of those issues. Expense - depends on what they find and how they diagnose the problem. If the mechanic is not familar with Toyota or family with this particular engine - they may opt for parts swapping for diagnosing the issues you are having. Generally this can get very expensive - as the emissions components are fairly expensive and labor is even higher, basically you are paying they to guess at the problem.

At the very least, get a diagnostic of the problem at hand, they'll report what they find, but you are not obligated to do the work there. Once you findout what the problem is - might be able to see if you can do it yourself. Most of the work in not diffucult to do - but does take some familiarity with the workings of the EVAP system and throttlebody. Some parts can be quite expensive to replace, but you generally find that it is the little bits that are causing the problems (damaged or missing hose, corroded connector, etc.).

2000 corolla, 270,000km which is about 168,000 miles. It seems like it runs ok, the shocks/struts are a bit worn so on speed bumps and such it drops almost rock bottom. No it doesnt consume any oil. i run castrol 5w-30. The major work done on the car was when the previous owner's niece (my friend) put diesel in accidently, and they had to do a major electrical job? thats wat he told me.(but hes not 100% sure) In addition to that, the car was in a minor collision and had the drivers side pushed in a little bit (no dents or grooves on the bumper but the bar where the hood latches onto got pushed in a bit) actually it was more tilted then pushed in. had a mechanic pull it back up so the hood would close properly. Oh and the car was sitting for 6 months before i took over ownership. Had to jumpstart but then the battery wont hold the charge, i then put some water on the battery and its been working since (about 4 months now).