Alright I have been getting code 0903. So I decided I would replace the evap canister vent control valve. I do that to find out I cannot clear that code so I then buy a OBD 2 reader to find out I have a evap vent control circuit malfunction. So basically right now the CEL is stuck on with a new vent control valve. Basically what are my options now? How do I go about figuring out the circuit problem. I already checked the harness to the vent control valve and everything is plugged in securely.

 

a vacume leak can also cause this to happen. check all of your evap system solinoids in the engine bay then check the evap canister area behind the drivers rear tire. i went to a junk yard and picked up all of the sensors and swapped them out. never had another problem.

but check to see if you have a vacum leak first.

 

Hi there:

I had the same problem with the EVAP valve and I did not clear the code before replacing it. Since the problem was already fixed, when I plugged in the OBD II scanner, it wouldn't pick it up.

You have to drain the ECU "internal" battery. You should do this only if you can leave your car battery unhooked for at least 24-30 hours straight, like on a wknd or if you have another car to use. Unplug the negative battery cable and tuck it away to the side so it doesn't flop back and contact the battery terminal. By draining the ECU power, the CEL will reset and you will be good to go. I have also heard the light will reset itself once the problem has been corrected, but my light was on for about a week after I replaced the valve, so I don't know how true that piece of info is.

Good luck!!!

Ted, Chicago

 

your 50/50 on this. leaving the battery unhooked will clear the ecu. but the code will come back. as for the ecu reseting its self, thats not true. the ecu will "cycle" itself through diagnoses modes. and will clear the light if the problem has not either A: been corrected or B: the problem has not occored in that time period. once it sees it again the CEL will come back.

 

I got a cel today comes up on my scan tool as a P1447. When i looked this up in my Haynes it says: P1447...0111 EVAP purge flow monitor fault? According to the manual and with my year (1995 cali emissions and 1996 later models), the EVAP canister is located on the left side of the vechicle behind the fuel tank...

 

Well I finally got the light to go off. After playing around some more. But now I reset the ECU and I drove 50 miles tonight and bam now I got 0304 and 0111 again. This is a never ending thing.

 

what did you work on?

 

lol i have the same exact problem. i reset it and all is well and then in like 50 miles the check engine light comes on. this is killing me and not to mention my inspection. i do believe that it it either the 4 nipple valve or the solenoid located next to the drivers side rear wheel.

anyone else?

 

..very likely if the VCV has been replaced and NOT fixed the problem, its the control solenoid valve ("4 nipple valve") under the hood. try that next, should take care of things.. thats what was wrong with mine when I got the evap code a while back..
DJ

 

I had the same problem, still do actually I'm sick of messing with it.
I replaced the vcv(bv) (has 4 nipples on it not sure if thats what your talking about), one of the nipples had been siliconed in place, so I replace it, no change, I took away all the electrical tape over the wires, found a corroded and broken connection, repaired it, car was fine, then got 09-03(EVAP Canister VCV) IS THIS not what I just replaced and repaired???

 

This is a sensor located on the canister on the back of the car behind the drive side rear wheel. I replaced this sensor thinking it was the problem then I couldnt reset my cel so I got an obd 2 reader to find out it was a circuit fault. I finally got the code to go on but now back at where I started with 0304 and 0111.

 

I got P1448 on my 2002 maxima - I also got a message that my gas cap was bad. I replaced the gas cap that didn't help. I'm not really familiar with the 4 nipple thing you guys have spoke of or how to get to the canister behind the rear drivers side - anyone got pointers on these things and where to get the replacement parts? Auto Zone said they didn't carry them.

error message said:
EVAP Canister Vent Control Valve (Open)

Probable Causes
1-Failed canister vent solenoid
2-Failed EVAP pressure sensor

which is the cheapest and easiest to fix first?

Thanks

 

I have a similar problem, p1446. I have checked the ECVCV (Evap vent solenoid on drivers side behind rear wheel attached to the EVAP canister) with a 12V circuit and the solenoid operates correctly/ vent opens and closes. I beleive my problem is a short/ resistance issue. I only get 9V at the harness connection, and the solenoid needs 11.7V- 12V to operate. I plug it in to the harness and look at the valve while someone else starts and turns the car off, and get no accuation of the solenoid.

You should look for any broken wires, corroded connections and of course vacuum leaks. Good luck these things take a while to pinpoint.

 

Had the CODE po 420 no idea if that was the right one but it was canister and close valve. i took the car on the highway and hit around 90 mph and the light went off 700 miles later it has never reappeared. maybe the valve was stuck who knows the dealer**** wanted 565.00 to replace canister..