The Evaporative Emission (EVAP) System helps to prevent fuel vapours in the tank from being released by burning them inside the engine. The powertrain control module of your vehicle (PCM/ECM), logs different fault code depending on the issue experienced by the EVAP System. One of these codes, P0443, is ‘Evaporative emission control system Vent Control Valve A” Circuit Malfunction.’ The “A” Circuit indicates a problem in the EVAP System Vent Valve or Control Circuit.
The EVAP system, as mentioned above, prevents fuel vapours being released into atmosphere. The canister is at the heart of the system, as it traps fuel vapours while the engine is turned off. The PCM opens the vent valve when the engine is running, and the conditions are correct. The fuel vapours will then be burned by the engine’s normal combustion. The PCM monitors both the vent valve’s control circuit and its integrity. It will set the P0443 error code if it detects a fault electrically with the vent valve or control circuit.
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What are the causes of fault code P0443?
- Faulty Drain Valve Problems relating to the drain valve circuit such as loose connections or damage cables
- Water ingress can cause corrosion or short-circuits
- Motor control modules can fail in rare situations
What are the Symptoms of Error Code P0443?
The engine fault light is usually the only symptom that comes with the P0443 code. You may also observe other symptoms if other codes are stored with P0443.
- The engine fault light is illuminated
- If the exhaust valve is left open, you may experience performance problems, such as the engine stuttering or hesitating to start
- Fuel consumption increases slightly
- The fuel tank cap will make a ‘puffing sound’ when it is opened due to excess pressure
How to Fix Fault Code P0443?
- Repairing damaged cables leading to discharge control valves and preventing further damages
- Replace the drain valve
Give the drain valve a command to activate it using a scanning tool. Listen or feel for a clicking noise from the drain valve. The drain valve may click only once, or depending on the model several times.
Remove the connector if you do not hear a clicking sound when you activate the scanner. Check for any damage or water on the connector and valve. Check the battery voltage of the supply cable with the key turned on. If you do have battery voltage, use a jumper cord to manually ground the power-side and listen for a clicking noise from the valve. If the valve makes a clicking noise, it is likely that the control circuit is malfunctioning. Replace the drain valve if there is no click.
How Serious is Fault Code P0443?
The engine fault light will illuminate even if there are no problems during driving. Fuel consumption may increase slightly if the EVAP system does not work properly.
