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P0443 OBD-II Trouble Code: Evaporative Emission Control System Purge Control Valve Circuit Malfunction

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P0443 code definition

Evaporative Emission Control System Purge Control Valve Circuit Malfunction

What the P0443 code means

P0443 is an OBD-II generic code that the engine control module (ECM) has detected a malfunction with the purge control valve or its control circuit. This could mean an open or short in the valve or circuit.

What causes the P0443 code?

  • The ECM has commanded the purge control valve to open and detected either an incomplete open circuit or a short in the circuit.

  • The cause of code P0443 can be a purge control valve internal open circuit or the connector is corroded causing loss of contact with the valve.

  • The code can also be set if the wiring to the valve is damaged between the ECM and the purge valve causing an open circuit if the wire is cut or a short if the wire is shorted to ground or a power source.

What are the symptoms of the P0443 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory.

  • You may notice a slight drop in fuel mileage if the vapor system is not working.

How does a mechanic diagnose the P0443 code?

  • Scans codes and documents the code in the ECM, views the freeze frame data see when the fault happened

  • Inspects the entire vapor purge valve wiring and system to include the purge valve connector for corrosion, damaged or loose connection or wires

  • Checks the purge valve vent for any blockage from dirt, debris, or spider webs

  • Performs a smoke leakage test on the fuel vapor system to try and locate the cause of the vapor leak using the test vapor port

  • Checks the purge control valve for proper resistance of valve and then check operation of valve using the ECM to control the valve

Common mistakes when diagnosing the P0443 code

  • Not checking and assuming the purge control valve is defective without doing a thorough diagnostics of the complete system to later find the wiring is broken or cut

  • Not verifying the failure and replacing parts that may or may not be the problem

How serious is the P0443 code?

  • Code P0443 causes the check engine light to go on and this alone will cause a failed emission test.

  • The code means the fuel vapor system control valve is defective or the circuit to it is not making the connection to the valve so the ECM lost control to the valve.

  • The vapor recovery and reuse system if not working correctly can cause a loss of fuel mileage.

What repairs can fix the P0443 code?

  • Testing and replacing the purge control valve
  • Repairing the damaged wiring to the purge control valve and secure from getting damaged again
  • Replacing the purge vent valve

Additional comments for consideration regarding the P0443 code

Code P0443 is a pretty common code that vehicles come in with today that causes the check engine light to come on. The most common cause is the fuel cap was accidently left off or not tightened securely after getting fuel. For this code the most common failure is the purge control valve has an internal open circuit or the vent valve will not hold in the vapors.

Need help with a P0443 code?

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The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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