OBDII emissions nightmare.... P0443 code evap emission control

[az_240]

I've had this dilemma for a while on my 97'(auto to manual swap) and after borrowing a working cat and the correct ecu Im STILL getting a code... P0443 Evap Emission Control System Purge Control Valve Circuit and I failed the gas cap test.

The guy at autozone looked at my emissions sheet and immediately said it's gas cap throwing that code... so I tried replacing the gas cap with a new aftermarket one and a new OEM one and had the codes erased both times and both times the code came back after several minutes of driving.

Autozone gave me a list of things it could be from their system.

-Blocked purge hoses
-Faulty canister vent control valve
-Plugged EVAP canister
-Faulty EVAP canister purge volume control

Gas cap is not even listed....

I do not remember getting this code when I had my auto ecu in.... I could not pass with that ecu because I was getting a transmission signal malfunction code. Are the manual and auto emissions systems slightly different somehow???

Has anybody here had this issue?

I've been unemployed for almost 2 years now so I have no money for a bunch of new parts and don't have a car to get around most of the time.

I'd really like to do a wink wink kinda deal.... if anyone knows someone please pm me. But if you have info on what I could do to pass without spending a ton of money I'd greatly appreciate it.

[Rabboni]

If you have the resources you should be able to test it yourself. First, Pull the canister. Its in the back next to the passenger wheel. There are only a few hoses and bolts so thats not a problem. if you shake it and charcoal crumbs fall out or you hear them moving around inside, or if the thing is cracked, then replace it. Next disconnect the hoses under the hood and blow air through them, if it flows then they are not plugged. If these two pass the test then you can be sure that it is either the vent or purge volume control valves or their wiring. Ill look up diagrams for those and tell you how to test them later... unless someone else wants to help out.

[az_240]

If you have the resources you should be able to test it yourself. First, Pull the canister. Its in the back next to the passenger wheel. There are only a few hoses and bolts so thats not a problem. if you shake it and charcoal crumbs fall out or you hear them moving around inside, or if the thing is cracked, then replace it. Next disconnect the hoses under the hood and blow air through them, if it flows then they are not plugged. If these two pass the test then you can be sure that it is either the vent or purge volume control valves or their wiring. Ill look up diagrams for those and tell you how to test them later... unless someone else wants to help out.

Thanks I'll check that stuff....

What exact hoses should I try to blow through?

[flip3d]

Good luck to you, sir. I have a bunch of EVAP codes as well.

There's a TSB floating around on how to clean the evap hoses. You could have some charcoal stuck in one of the valves or one of the evap solenoids could have gone bad. My advice would be to just leave it alone. It doesn't affect drivability at all.

[az_240]

^hahahah I wish I could just leave it alone.... but I need to pass emissions so I can drive this bitch.

[Rabboni]

I just checked in my fsm and it didnt mention any of the things your friend at autozone told you to check. So, forget all the things he told you to check. He is retarded.
Your Evap Emission Control System Purge Control Valve is under the hood sitting on top of the intake runners. It has two vacuum hoses attached to it and a 2 wire connector. One wire is brown and should have battery voltage at all times. The other wire is yellow with a red tracer. The Y/R wire goes to the ecm pin 105. So check to make sure you have battery voltage at the brown wire, and that the Y/R wire isnt shorted or open, and if both wires are good then replace the valve.

[Z U L8R]

I just checked in my fsm and it didnt mention any of the things your friend at autozone told you to check. So, forget all the things he told you to check. He is retarded.
Your Evap Emission Control System Purge Control Valve is under the hood sitting on top of the intake runners. It has two vacuum hoses attached to it and a 2 wire connector. One wire is brown and should have battery voltage at all times. The other wire is yellow with a red tracer. The Y/R wire goes to the ecm pin 105. So check to make sure you have battery voltage at the brown wire, and that the Y/R wire isnt shorted or open, and if both wires are good then replace the valve.

x2

that is the exact answer

the code is specifically for the purge valve circuit, so smack a fool for talking about foolish clogged hoses lol.

this is a purge valve or wiring problem not a hose. you should be able to hear the purge valve click if you give it a power and a ground on it's two terminals.

power probe 3 ftmfw

[email protected]

Dave

[bikrman2]

Deff pp3 ftw! I would deff start with that valve. I replace them at work almost weekly. also make sure the vacuum lines to and from it aren't cracked.

[Z U L8R]

http://www.aeswave.com/new/www/images/products/856/PP-3.jpg

one of the best quick n easy diagnostic tools, definately worth it's price 3 times over.

most people don't know all it's features but it has 5 modes. you can also measure peak voltage inductively. like lets say you're suspecting an intermittent problem with one of your coil packs. you can lay it over the coil packs and measure their peak voltage. they'll all be pretty close to the same, then you'll get one that's way lower/different and there you is lol

anywho, gl with ur car man

Dave

[az_240]

Okay I already had the back end up and the wheel off so I checked everything out in the rear and shook the canister around... everything seemed fine. Canister sounded like it had a single small pebble in it.

I checked all the evap lines ontop of the intake and they all seem fine

Im about to check the valve now.... My multi meter has a ton of settings on it though and I have no idea what one to use....

Its the green solenoid correct? How do I check for voltage? The pins are basically female on the plug and I dont think the probe thingy will fit...

Thanks for the info

[Rabboni]

To test for voltage in the brown wire put the tester in direct voltage mode (Not the curvy line voltage symbol on the meter, the one with the dotted line). Put one lead touching the metal in the connector hole corresponding with the brown wire, and the other lead on battery negative. Should read battery voltage. To accurately test the Y/R wire you need to disconnect the ecm connector. Now set your meter to resistance and measure from the valve connector to the ecm connector pin 105. Resistance should be very little. Also check from the connector to battery negative to make sure there arent any shorts to ground.

[az_240]

^I did this and my multimeter reads 0...

My voltmeter is switched onto V... with the line above the dots.
The black wire/probe is on the negative terminal. The red wire/probe is plugged into the V/speakersymbol/m/A/*F outlet the other outlet shows 10A which im assuming is amps and I do not want to use. The probe is touching the inside of the plug where the metal is and I get nothing.... I tried this on another plug and also got nothing.

What am I doing wrong?

[Rabboni]

Either you are doing it wrong or you found your problem. Put the leads across the battery terminals. If you get 12.6 volts (or something close to that) then your meter is set up properly. If, after you have confirmed the meter is set up properly, you test for power in the brown wire and you again get zero, then your CEL is on because there isnt any power getting to your solenoid valve.

[az_240]

I put the leads on the battery terminals and got 12.4.

Tried the plug and still got 0 on the brown.

Is it possibly the ecu?

[Rabboni]

Right now your concern is that you are not reading voltage on a wire that should always have voltage. Now you need to figure out why it doesnt. It runs of fuse 14 of your under dash box (top left one), but since that is your only code it isnt the fuse. My guess is that there is an open in the power (brown) wire where it splices earlier in the harness. Now you have a few options:
1. Get a new harness (totally unnecessary to fix only one wire)
2. Run an overlay from the fuse box to the plug
3. Run a brand new wire from the battery (looks ugly, and might fail visual inspection)
4. Buy some splice locks and splice into the harness earlier and out of sight. (This is what i did to fix that code when i had it)

[az_240]

Just tried turning the key on and measured the brown wire and I got 12.2 volts.

So am I good now or should it really have voltage at all times? Try the yellow ecm wire?

[Rabboni]

Oh crap, my bad. If there is voltage while the key is on then it is good. Im doing most of this diagnosis by memory, and it harder when you cant see it. Now you have to test the Y/R wire.

[az_240]

its all good... I was thinking why would there be voltage all the time to this solenoid and just decided to try it out.

I just checked the y/r wire and pin 105 using the resistance sound setting and I got a clear signal so im guessing thats not the problem either.

On to replacing the solenoid I suppose... if that does not fix my problem im going to blow my car up.


Thanks a lot for your help man... id be lost witout you.

[az_240]

I just checked the resistance of the solenoid using the 20k setting and im only getting a 0.04. Does that sound right? Any other ways I can check it?

I want to be sure my solenoid is bad before hunting around for a new one.

[Rabboni]

Im almost positive that .4 ohms is a shorted solenoid. Only other way i could thing to check it is to supply your own power and ground and see if it clicks. Just unplug it and run wires from the battery terminals to each pin in the solenoid. If you hear the solenoid click when the circuit is completed, then the solenoid could be good. I dont think the thing is that expensive anyway. If the wires are good, then by process of elimination the solenoid has to be bad.

[az_240]

Thats what another guy said... its probably shorted out.

I did accidently blow out my main fuse a while back while installing an alternator... it probably shorted this thing out.

Ill try hooking it up to my battery to see what happens.

Edit: just hooked it up to the battery and it makes a click... tried blowing through the nipples on the solenoid and it does switch/stop airflow.

so SHIT!!! it looks like this solenoid works afterall...now what

[az_240]

Should the solenoid click when plugged into its plug? I held the solenoid while someone turned the car to the on position and it did not click.... I remember seeing 12.4 volts when checking the plug.... id imagine it should click when the car is turned to the on position.

[Jonnie Fraz]

Ok please do yourself a favor and check to see if your ECU is working correctly. We were chasing a simular problem with my brothers ODBII car and turs out that the ECU was bad. He spent like a grand chasing bad valves and sensors...turns out the the ECU had a bad pin. See if you have a buddy that you can swap ECU's with.

[fos240]

i had that same code a long time ago. the stillen strut tower bar i was using cut one of the rubber hoses to that solenoid. check to make sure you don't have any leaks anywhere involved with that solenoid or system.

also, iirc that works in conjunction with the evap canister in the back. so even if that solenoid is working but the one in the rear isn't, it will still throw the code. seems like someone else had this same code and they cleaned the solenoid in the rear.

frankie

[Z U L8R]

last but not least see if you can use a smoke machine to find any evap system leaks, but more than likely it's a bad circuit in the ecu since everything else tests good.

it'd be easier if i had the car here to diagnose but it sounds to me that you're testing it properly therefore last step = "try known good ecu"

Dave

[az_240]

If I put my old auto ecu shouldnt this code pop up along with the tranny malfunction code?

I dont remember seeing this code when I had them read.

I'll try it out.

Edit: Put the old auto ecu in and the P0443 went away but in its place I got P1445 which is the evap canister purge volume control valve and the light turned on immediately after clearing the codes... didnt even crank the engine over.

Now im lost.... why am I getting two different codes with two different ecus!?!?! faaaaark

[Jonnie Fraz]

Edit: Put the old auto ecu in and the P0443 went away but in its place I got P1445 which is the evap canister purge volume control valve and the light turned on immediately after clearing the codes... didnt even crank the engine over.

Now im lost.... why am I getting two different codes with two different ecus!?!?! faaaaark

You do not want the P1445 evap canister purge volume control valve to be bad. It is a royal bitch to change, and it is $300.00+ from Nissan. This is the valve that is in the middle of the upper and lower plenum. This sound so familar.

[Rabboni]

Man I know these things are super tough to deal with, because I just went through it last month. I cant really do anything else to help you without the car actually being in front of me. If you can, download the fsm. It has the diagnostic trees for every code the car can throw. It will tell you step by step what to test, and how to test it, to find the culprit.

[az_240]

I appreciate the help... I have a friend who is gonna help me diagnose it. What a bitch this has been.

I have a feeling its one of these solenoids or that valve under the intake manifold. Not sure why else I would throw a code immediately.

Edit: Just checked for vacuum to the solenoid and I'm getting none with the car running. My FSM says I should be getting vacuum to that solenoid around 2k rpm.... im not sure if the car is supposed to be in gear and running though... can anyone confirm?

[az_240]

So my life has been at a standstill since I cannot even leave my house. I'm literally going insane and need to fix this asap.

I checked on a friends car and he does not get any vacuum either so that is not my problem.

The guy that was gonna help me backed out.

Im now just trying to figure out a way to test the code P1445 evap canister purge volume control valve which is located under the intake manifold.

I was told there is a sub harness that I can disconnect and I can just test the connector for resistance to see if the valve is good without removing it from under the intake manifold.
The FSM gives no information on this.

Does anyone have any idea where I could find this connector?

Any info is appreciated.

[Jonnie Fraz]

The sub harness goes from the valve to the front of the manifold. There are two plugs right above the throttle boddy. Follow the harness from the valve to the plug that has six wires and follow the test procecure in the FSM at that plug.

[az_240]

^Thanks! I found the 6 wire plug above the throttle body and tested it according to the FSM.

For resistance I only got 19.2. The FSM says I should be getting a reading of appx 30.

Is the resistance off enough to assume this valve is bad?

[Pacman]

Forgot to add this to the PM, going through the subharness should increase resistance just a little (harness is small). I'd test mine for comparison but my ohm meter is in my toolbox at work. Heat will also increase resistance. Yours is lower than spec, by 10 ohms. I'd hate to say replace a $300+ valve and go through the trouble of replacement. Like I said, I could've sworn that there are pins you have to move for the swap and different computers.

Oh yeah, Mr. Fraz, I still want that brace I never got back to you on. Sorry about that. PM me if still available.