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Discussion Starter #1
I recently connected a hose running from the pcv valve down to the street and also disconnected the valve cover breather tube from the air intake. I then put vacuum plugs on the back of the IM and also on the air intake.

Somehow, it appears that the ECM has found out about this modification as I now have a check engine light with a p0443 code. To my knowledge there aren't any sensors inside the engine that monitors the amount of blow-by, so my question is how does the ECM know?
 

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Hatch Nation #136
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The simplest reason would be if you have one of the plugs incorrectly installed and it is letting air past. This would change your vacuum and trigger a code.
 

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BACON?
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that code is for the EVAP system not the PCV system.

The Evaporative emission control system works to control Hydrocarbon emissions emitted when the gasoline evaporates. The system contains a few major pieces, the canister, the lines, the purge valve and the canister close valve.

Fuel vapors are contained in the evap canister, when the canister needs to be purged the ECM closes the vent valve and opens the purge valve. One end of the purge valve is located on the intake manifold. A vacuum will then "suck" the captured fuel vapors out of the canister and in to the engine, where it can be burnt instead of released to the atmosphere.

Your code is a P0443- Evap purge valve circuit malfunction. I don't know what you have for tools or experience so i will give you a couple ideas for testing. You can run the car and wait for the evap to activate, then while activated check for power and ground at the purge valve. Typically a dealership would use a scan tool to activate the purge valve for testing, I am guessing you can't do this.

Another test you could do is remove the valve from the car, the supply 12 volts to the valve. you should hear a click. When no power is supplied the valve will be closed, blow in to one end and see if air comes out the other. Now, apply the power again and see if air comes out, It should.


This should get you headed in the right direction. Please ask any questions you might have. Good luck.

EDIT: did you disconnect the purge valve line from the intake manifold, that would be a logical explanation for the code. because there is no vacuum created the ECM thinks that the purge valve is stuck closed.
 

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Discussion Starter #4
Ahhh... that little canister thing mounted over the exhaust manifold (was wondering what that was), yes I did disconnect the vacuum line that runs from it to the IM, but I plugged it back in afterwards. Maybe I was too rough with it and cracked it, as I did have to bend it out of the way to get the IM off.

Thanks alex, I'll check that later when I get home. I knew something was strange if it were the lack of blow-by that was causing the code.
 

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The system actually checks for leaks and flow so if you disconnected or plugged something in the EVAP system it will fail the test and set a code.
 

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Discussion Starter #6
It wasn't my intention to interfere with the EVAP system, only the PCV, although as I stated earlier I did have to temporarily disconnect the purge line from the IM in order to get it out of the engine bay, but I may have damaged the purge line or the valve when I flexed the purge line out of the way.

I'll have to check when I get off from work.
 

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Discussion Starter #7
Wouldn't you know it, I was having problems at first removing the purge line from the IM, so I was going to disconnect it from the canister's end but in the process I unplugged the harness from the canister and forgot to plug it back up.

After plugging it back in, and letting the car idle for a while, the CEL code went away.
 
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