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I have a 2007 Kia Spectra EX giving a P0449 DTC (vent valve solonoid ckt).

I have made sure the gas cap is not leaking; I now have the gas tank removed and the EVAP/Canister system removed from the gas tank and am trying to troubleshoot.

First, where can I find an accurate description and diagrams of the emissions system (theory of operation, component descriptions and testing, etc.)?

Next, I have tested the vent valve solonoid (CCV) and it is definitely GOOD (it is normally open, apply 12V and it closes air-tight).

How can you test the fuel tank pressure sensor (removed from tank)? I checked the terminals with an ohmmeter while applying pressure/suction to the tube and I get nothing - all terminals always open (but I don't know if this is a simple resistor-type sensor or maybe some kind of semiconductor or something making this an invalid test).

I blew a lot of dust out of the vent filter, but I don't think it was stopped up. What about the charcoal canister and auxilary canister (how to tell if they might be bad)?

I have not checked to make sure all the trigger signals are present - have to do that when I get it all back in the car.

Any advice or tips on troubleshooting this system?
 

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Discussion Starter #2
Same PROB again in 2016-2017

I have a 2007 Kia Spectra EX giving a P0449 DTC (vent valve solonoid ckt).

I have made sure the gas cap is not leaking; I now have the gas tank removed and the EVAP/Canister system removed from the gas tank and am trying to troubleshoot.

First, where can I find an accurate description and diagrams of the emissions system (theory of operation, component descriptions and testing, etc.)?

Next, I have tested the vent valve solonoid (CCV) and it is definitely GOOD (it is normally open, apply 12V and it closes air-tight).

How can you test the fuel tank pressure sensor (removed from tank)? I checked the terminals with an ohmmeter while applying pressure/suction to the tube and I get nothing - all terminals always open (but I don't know if this is a simple resistor-type sensor or maybe some kind of semiconductor or something making this an invalid test).

I blew a lot of dust out of the vent filter, but I don't think it was stopped up. What about the charcoal canister and auxilary canister (how to tell if they might be bad)?

I have not checked to make sure all the trigger signals are present - have to do that when I get it all back in the car.

Any advice or tips on troubleshooting this system?

I took everything all apart back then, cleaned everything up very well, problem went away for a couple of years. Now, it's back, maybe slightly more intermittent than before. MIL and code P0449 seem to come and go.

I am about to do same thing again, any suggestions before I begin???
 

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From code description, it sounds to me like a poor wire connection(not just the molded plug part but individual wires in it). Or a chaffed/breaking wire in that parts wire harness.
 

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From code description, it sounds to me like a poor wire connection(not just the molded plug part but individual wires in it). Or a chaffed/breaking wire in that parts wire harness.
You may be correct, but test the system first, then a simple circuit drop test..

... Philip
 

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Discussion Starter #6
Problem is back. It managed to go away last year for long enough to get it inspected, but shortly after, MIL came back on and has stayed on for several months now. I have this month to get it inspected, so I have to get it fixed. This kind of work has become difficult since I injured my back, but I can't afford to get fixed at dealer/mechanic. So, I am back up under the car, trying to get at the EVAP parts without fully removing the gas tank. I'll keep this thread posted on how it goes.
 

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Discussion Starter #7
Last time I worked on this, a thorough cleaning of all parts involved seemed to fix the problem. I live out in the country down a 1-1/2 mile long dirt road, so the underside of the car is always caked up with sand and concrete dust (because they often use recycled crushed concrete to maintain the roads here).

I am also running into a nomenclature problem. In trying to identify all the components in the EVAP system, I ran across something called a Canister Close Valve (CCV) and an EVAP vent valve - I have begun to guess that these two names refer to the same component (or else there is another part that I can't find and different troubleshooiting guides are in conflict with each other) - any thoughts?
 

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Yes...they are 2 different parts. Have you actually scanned the computer for actual code(s) to KNOW for sure that it is EVAP related, or are you guessing it is the same concern?
 

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Discussion Starter #9
... Have you actually scanned the computer for actual code(s) to KNOW for sure that it is EVAP related, or are you guessing it is the same concern?
I have a scantool and I am reading a P0449 code- when I had the same problem a few years ago, I had also taken it to Autozone and they read the same P0449 code. I have done goo-gobs of research since then and I have learned a lot about the components and general operation of the EVAP Control System. I have become fairly confident that the generic component called the "vent valve" has many different names according to various manufacturers and is called the Canister Close Valve (CCV) in Kia language (I have read enough functional descriptions, both generic and Kia, and seen that 'these' components perform the same function and are located in the same position in the system).

The biggest remaining question I now have is what condition-circumstance actually sets the P0449 code? I have run into conflicting data on this point. Some sources say it is purely an electrical condition (ECM detects an open/short circuit or excessive/insufficient resistance in the CCV solenoid, i.e., solenoid open or wiring problem). Other sources say it is result of a failed leak test (pressure/vacuum differential failure). But if the latter were the case, it seems to me that there should be other DTCs that accompany the P0449 (which I do not). And it also seems that different manufacturers have slightly differing conditions that set a P0449.

I have also learned (I think) that the CCV is only employed in system diagnostics that test the integrity of the EVAP system (i.e., a leak test). Then the next biggest remaining question is when do these diagnostics take place - IOW, when does the ECM send the energizing signal to the CCV to close it? I do not have an advanced scantool that will command the ECM to energize the CCV, so I need to discover when the ECM will naturally energize the CCV so I can troubleshoot the electrical circuit between the ECM and CCV (I don't have any schematics or wiring diagrams for this car, either). There are two wires that go to the CCV; one is 12V, other is an open-collector output of the ECM which goes to ground to energize the CCV. Exactly when is this signal activated?
 

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Discussion Starter #11
FYI, I now have the fuel tank on the workbench, I have disassembled the ECS attached to it. The air filter had grunches of dust in it; last time I just blew it out, this time I have replaced it. I have tested the CCV and it seems to work fine (also gave it a thorough cleaning). I have attempted to "recondition" the charcoal canister by alterenately blowing fresh air in and vacuuming out (using low pressure) to hopefully restore its fuel vapor absorbing ability a little bit.

The air filter was cheap; new CCV solenoid is expensive (would rather not replace if possible), so what I am hoping is that maybe it got dirty and leaked a little and now it is OK. Only other concern is that a service manual I found says the CCV solenoid should be 23-26 ohms, mine reads 20 (is that enough for ECM to trigger a fault? I would guess not). It is the original factory CCV (I have had the car since it had 12,000 miles - now has over 200,000 miles.

The only thing I have not done is rung out the wiring of the CCV 12V and ECM control wiring (see previous post).
 

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Hi rev_daddy_sp...
I have read where over filling the gas tank can cause problems with this valve and also the carbon canister...
I have also read where these valves just get stuck either open or closed...
You might want to check the connections on this valve also as it is under the car and subject to corrosion from water and salt being thrown in that area...
Dave
 

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Discussion Starter #13
...
... over filling the gas tank can cause problems ...
... just get stuck ...
... check the connections ...
.
I also have heard that repeated overfillings can be damaging - thinking this to be true on almost any modern car.

I didn't test the valve/solenoid until I had already taken it apart; it is quite possible it may have been sticking before - after I cleaned everything up, it worked (tested) like a champ.

I have not yet put it all back together (been cold and rainy last few days), but I am scrutinizing the electrical connections - they looked pretty good when I first disconnected them and there were no obvious broken wires. Since I have had this problem a couple of times before and never found any real hard cause/source of problem (other than possible contamination), I have manufactured a test pigtail right at the input to the solenoid that I can hook a meter or a power source up to to help troubleshoot the electrical part. -- I have learned that the 12V wire coming to the CCV solenoid is fused at the same fuse that feeds the injectors and is labelled "INJ" in the fuse box; so that one is easy to follow/test. The other wire that goes to the ECM is tougher; I haven't yet learned what pin of the ECM it goes to (or what color the wire is) (but I think the ECM is on the floor under the dash near or under the console, I haven't put my hands on it yet). I want to be able to make an overlay harness in case it starts to look like there is a wiring problem between the CCV solenoid and the power/control. Hopefully, the ECM itself is not at fault.

I still would like to know when or under what circumstances/conditions the ECS does the leak test (i.e., closes the CCV), because I can hook a noid light up to my new pigtail to verify that a proper activation signal is getting to the CCV solenoid.
 

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Discussion Starter #14 (Edited)
OK. All back together now. Seems to be working fine. I have been driving for almost 5 days now, maybe a total of about 200 miles, and probably about 15 drive cycles and no more MIL. I have filled up the gas tank once since fixing, and it filled nicely without any restriction (but that never was a problem). Once again, it seems that cleaning the gunk out (and this time replacing the contaminated fuel tank air filter) fixed it.

There is something new that is a little bothersome. Now, occasionally, it is a tiny bit hard to start on the first try. Every once in a while, it will act like fuel is not immediately getting to the cylinders and it will take 2-3 seconds of cranking to get it to start up. And then even more infrequently it may stall out after starting, as if it were starved for fuel. But always a second attempt to start and it starts right up with a 1/2 second of cranking, just like it always used to do.

So far, it has never failed to start, and more often than not, it still fires right up on the first try. But that 25-30% of the time that it seems to falter a bit at first leaves me wondering, what has changed or what could I have done to create this. It is possible that a new and completely coincidental problem has occurred.

Any thoughts???

P.S. I did find a wiring diagram in a factory service manual that I didn't know I had - the switch side of CCV goes to pin 79 of the ECM.

P.P.S. I forgot to mention, that it makes no difference whether the engine is hot, worm or cold, seems very random. Also, I did disconnect the battery for about 20 minutes to fix a battery terminal right after putting it all back together - maybe it is still in "learn" mode ???
 

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Sounds like one way check valve on fuel pump. Simple test is first thing in morning, turn the ignition on, wait 3 seconds, turn ignition off, then on agin for 3 seconds and then crank the engine. This builds up fuel pressure, and if it fires right up, that's the issue. Live with it or change the pump, which is real simle on these cars under the back seat.
 
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