The OBD2 error P0443 code activates when your engine computer detects an issue with your EVAP purge control valve circuit. A stuck or faulty valve in this system can cause your vehicle to emit more harmful compounds than it should. It can also make your engine run too lean and reduce your fuel economy.
Fixing the P0443 code can vary in difficulty. In some instances, repairing a wiring issue or vacuum leak is all you need. Other times, you may need to replace components, or even fix more serious electrical problems. Read more about this code below to help you diagnose and repair it correctly.
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P0443 Code Definition
P0443 Code Definition (Generic): Evaporative Emission Control System Purge Control Valve Circuit
P0443 BMW Code Definition: EVAP System Purge Control Valve “A” Circuit
P0443 Dodge Code Definition: EVAP System Purge Control Valve “A” Circuit
P0443 Ford Code Definition: EVAP Canister Purge Solenoid Circuit Malfunction
P0443 Jeep Code Definition: EVAP System Purge Control Valve “A” Circuit
P0443 Nissan Code Definition: EVAP System Purge Control Valve “A” Circuit
What Does P0443 Mean?
The evaporative control (EVAP) system in your engine repurposes the fuel that escapes from your tank. By redirecting the outgoing airflow back into the system, fewer emissions are able to escape into the atmosphere.
Along with controlling emissions, the EVAP system helps to control the temperature of the car engine. This makes it an especially important component for the correct operation of your vehicle.
The movement of the purge control valve is directed by the engine control module (ECM) or powertrain control module (PCM). When the ECM or PCM detects a short or other malfunction with the purge control valve, it will trigger the P0443 trouble code.
The ECM or PCM monitors the voltage of the ground circuit and the purge solenoid to ensure the purge valve is operating correctly. The voltage of the ground should drop nearly to 0 when the purge solenoid is active. If the purge solenoid isn’t active, the ground voltage should be high. A failure to register these voltage changes will also activate the P0443 trouble code.
While P0443 is a generic powertrain code, and therefore applicable to any OBD2 vehicle, the repair steps can vary between makes and models. You should check your vehicle manual before starting in on your diagnosis.
What Are The Symptoms Of the P0443 Code?
In some cases, you won’t experience any drivability issues from the P0443 trouble code. Other drivers may experience one or more of the following symptoms:
- Activation of the check engine light
- Lean air-to-fuel ratio
- Rough idling
- Reduced fuel economy
- Whooshing sound or high vacuum in the gas tank
What Are The Causes Of P0443?
- Short or open in the wiring of the purge valve or circuit
- Damaged wiring in the EVAP system
- Faulty purge vent valve
- Faulty purge valve solenoid
- Internal short in purge solenoid
- Faulty ECM or PCM
How Serious Is The P0443 Code?
The P0443 trouble code is of low severity. Your vehicle will still operate fine even with this code active. You will expend more fuel and emit more harmful emissions until you repair the code, however. At the very least, you’ll need to clear this code before your next emissions test.
How To Diagnose And Fix The P0443 Code
Tools you’ll need:
- Use an OBD2 scanner to check your vehicle for other trouble codes. If you see similar and related codes, such as P0440–P0449, P0452, P0453, P0455, or P0456, it can help guide your diagnosis.
- Read the freeze frame data, identifying the conditions under which the code was set.
- Clear the codes and take your car for a test drive to see if P0443 returns. If it does, evaluate your other symptoms. High fuel pressure tends to indicate the valve is clogged or stuck closed. A lean air-to-fuel ratio or rough idle, on the other hand, points toward a valve that’s stuck open.
- Use your scan tool to activate the purge solenoid. You should hear a clicking from the solenoid when you do this. If you don’t hear a clicking, unplug the connector and check for moisture, corrosion, or other damage.
- Turn on your ignition without starting your engine. Use a multimeter to test the voltage of the feed wire. If it checks out, use a jumper wire to manually ground the control. If the purge solenoid clicks, you’ve isolated the problem to the control circuit. If the solenoid still fails to click, it is defective and needs to be replaced.
- Monitor the fuel tank pressure readings with an OBD2 scanner. A low fuel pressure likely indicates a vacuum leak. Inspect the fuel cap for damage, and make sure it’s screwed on properly. A high fuel pressure suggests a clog or stuck valve. Visually inspect the purge valve vent for blockages.
- Use a smoke machine to identify vacuum leaks. Replace any damaged hoses and tighten any loose connections.
- Visually inspect the wiring of the EVAP system. Make sure all wires are firmly connected. Also, check the wires and connections for corrosion or other damage, and replace as necessary.
- If the code still will not clear, you may have a more significant electrical problem. Take your vehicle to a mechanic for further diagnosis.
Common Mistakes To Avoid While Diagnosing The P0443 Code
Inexperienced mechanics may replace the purge control valve before conducting a full diagnosis. While this may be the cause of a P0443 trouble code, you should thoroughly inspect the wires and connections before replacing any components.
Tips To Avoid P0443 In The Future
One easily avoidable cause of the P0443 is a loose or damaged gas cap. Make sure you firmly replace the gas cap every time you fill your tank.
You can also avoid a P0443 trouble code by preventing other vacuum leaks in your system. Make sure all hoses are firmly connected, and that there are no nearby components that could damage them. Do the same with the wiring to avoid electrical problems.