P0443 Code: Evaporative Emission Control System Purge Control Valve Circuit Malfunction

The evaporative emission control system (EVAP) is one of the most important components of the vehicle. This system prevents the fuel vapors from releasing into the atmosphere. The EVAP system sends its information to the powertrain control module (PCM). The EVAP system also contains a purge valve. When your PCM detects an issue with the purge control valve, it triggers the DTC P0443. This article mainly explains the P0443 code symptoms, its causes, and how to fix it.

P0443 Code Definition

P0443 code stands for “Evaporative Emission Control System Purge Control Valve Circuit Malfunction.”

What does the P0443 Code Mean?

The P0443 code indicates that your powertrain control module (PCM) detects an issue with the EVAP system purge valve or its control circuit. This could mean a short or open circuit or valve.

P0443 code

Modern vehicle models contain an evaporative emission control system (EVAP). The main function of the EVAP system is to stop the release of fuel vapors into the environment.

The EVAP system of your vehicle uses to collect the raw fuel that exits the fuel tank and fuel system. The EVAP system transfers this data to the PCM, which utilizes this data to regulate vehicle emissions.

The EVAP system transfers the collected fuel vapors back into the engine intake, from where they are transferred into the engine combustion chamber. This process is completed by metering these fuel vapors via a purge control valve. The purge control valve is activated by the delivery of ground () through the engine PCM.

The PCM triggers the P0443 code when it detects a purge control valve fault or a short in the purge valve circuit.

Similar to code P0443, codes P0444 and P0445 are also associated with the purge control valve.

Symptoms of the P0443 Code

  • Check engine light is flashing
  • Rough idling
  • Poor acceleration
  • Poor fuel economy
  • A reduction in engine performance

Causes of the P0443 Code

  • A bad purge control valve 
  • The wires of the purge control valve are damaged
  • Loose electrical connections of the purge control valve or EVAP system
  • Bad vent valve solenoid
  • Damage in the EVAP system
  • Bad purge valve solenoid
  • Faulty PCM

How to diagnose the P0443 Code?

  • Use an OBD2 scan tool to verify the existence of the P0443 code.
  • Use the freeze frame data to identify all the existing codes.
  • Clear the stored codes and perform a test drive. If the code returns, move forward for further inspection.
  • Properly inspect the wiring and connections of the purge control valve for corrosion or damage.
  • Fix the loose connections of the purge valve.
  • Inspect the wires and connections of the EVAP system.
  • Inspect the purge control valve for a blockage due to spider webs, debris, or dirt.
  • Perform a smoke leakage test on the fuel vapor system to find the reason of the vapor leaks using the test vapor port.
  • After disconnecting the purge solenoid connector, turn on the car’s ignition switch and check for the existence of a 12v positive at one of the connector’s pins. If there is no voltage, then you need to move further to find the wrong open circuit.
  • If one of the purge solenoid’s pins were found to be hot (+), then again connect the connector in question, and jump ground directly to the pin opposite the solenoid’s positive feed.
  • Inspect your purge control valve for proper resistance of the valve
  • Inspect the purge control valve for damage. If it is bad, replace it.
  • Inspect the PCM for fault.

Common P0443 Code Diagnostic Mistakes

  • Replacing the purge control valve without inspecting the electrical connections and wires.
  • Lack of error checking and replacement of any defective parts.
  • Not clearing the PCM memory after fixing the problem.
  • Replacing the unnecessary parts.

How serious is the P0443 Code?

The P0443 code is considered a serious trouble code. It can seriously affect the drivability of the vehicle, such as engine knocking, poor fuel economy, poor engine idling, and engine stalling. This code mainly indicates an issue with the evaporative emission control system (EVAP) of your vehicle.

The EVAP system helps to reduce the emission of exhaust gases. An issue with this system may increase the emission of the exhaust, and your vehicle may fail the emission test. Driving under such conditions may severely damage the internal engine parts.

What repairs can fix the P0443 Code?

  • Replacing the bad purge control valve
  • Fixing the damaged or corroded wiring to the purge control valve
  • Fixing the loose connections to the purge control valve
  • Fixing the damaged electrical wires and loose connections to the EVAP system
  • Replacing the bad purge vent valve
  • Replacing the faulty PCM
  • Cleaning the clogged purge control valve

How to Replace Purge Control Valve?

FAQ Section

What is an EVAP System?

The EVAP system is used to collect the raw fuel that exits the fuel tank and fuel system. This collected fuel is transferred into the engine intake.

What are the symptoms of the P0443 Ford?

  • Poor fuel economy
  • Check engine light is flashing
  • Rough idling
  • Poor acceleration
  • A reduction in engine performance

Can I drive with the P0443 code?

Yes, you can drive with the diagnostic trouble code (DTC) P0443 for a short time. However, you shouldn’t drive for a long period with this code. This code may produce different issues, such as rough idle, engine stalling, or poor acceleration. Driving with this code for a long time may damage the internal parts of your engine. Therefore, you should fix it as soon as possible.

What are the causes of the EVAP system failure?

The EVAP system may fail due to one or more of the following causes:

  • A leak in the gas cap
  • Loose gas cap
  • Leak in the hose
  • Issues with the purge valve
  • A rusty fuel filter pipe

What are the symptoms of a bad EVAP system?

  • Engine stalling
  • Poor acceleration
  • Rough idling
  • Poor fuel economy
  • Failed emission test
  • Hard to start the vehicle
  • Check engine light illumination
  • A quick reduction in the fuel
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