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P1443 Evaporative Emission Control System Vacuum System

Fix code P1443 Evaporative Emission Control System Vacuum System – Purge Control Valve Solenoid

If you have a P1443 Evaporative Emission Control System Vacuum System – Purge Control Valve Solenoid trouble code, this post will help you understand what it is and how to fix it.

The evaporative emission control system checks to make sure there are no leaks in the lines that run from the gas tank to the charcoal canister and up to the engine. It also checks to make sure the gas cap is sealing correctly.

When you fill your car with gas, the vapors in the tank get forced into a canister filled with activated charcoal. Also, on a hot day as the gas heats up and vaporizes, those same vapors push into the canister where they’re stored. But the charcoal can only hold so much vapor. At some point it has to be emptied. The emptying process is called “canister purge.” Here’s how it works.

The computer orders a canister purge by powering open a PURGE solenoid. That opens the vacuum line between the canister and the intake manifold. At the same time, it opens a VENT solenoid. That allows fresh air into the canister. So the engine is literally sucking out the gas vapors and purging the canister with fresh air. The computer has to adapt its fuel strategy to take advantage of all the extra gas vapors coming into the engine.

The computer notices the canister is empty when it detects a leaner condition (all the vapors are used up) and it resumes normal fuel delivery. Some car manufacturers then close the VENT solenoid but leave the PURGE solenoid open. That creates a vacuum throughout the entire fuel storage system. Once the correct vacuum is reached, it closed the PURGE solenoid and waits to see if the vacuum holds. If it doesn, the system passes the test. If it detects a leak, it sets a code.

The computer also watches the vacuum activity. If it commands a vent or purge solenoid, it expects to see a change in vacuum. If it doesn’t, it sets a P1443 code.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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