P0443 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Causes

This OBD-II code can be caused by several different factors. It could happen because of an electrical issue, such as the ECM directing the purge control valve to open and then detecting a problem in the form of either an incomplete open circuit or a short. 

Another issue that could cause this code is a corroded connector, which can cause loss of contact with the valve, rendering ir inoperable.

A third way this code can be set is if there is damage to the wiring somewhere between the ECM and the purge valve. 

Finally, you might get this code if there is a physical problem causing the purge control valve to work incorrectly, such as a blockage cause by dirt or debris.

Symptoms

There are several symptoms you might notice in the event that your vehicle develops this problem. First, the Check Engine light will be illuminated. This in itself is not that unusual. Also, the P0433 code is set in ECM memory.

Another symptom you might notice will be a slight drop in your overall fuel economy, as the engine is unable to work at peak performance when this happens.

Diagnosis

To verify that this code is telling you the right problem, the first thing you should do is go over the freeze-frame data to see when exactly the fault happened. This can be done by scanning the codes and documents in the ECM. Clear the code and run the car again to see if it reappears. If it doesn’t, it could mean there is no problem, or that the ECM detected an issue but wasn’t able to diagnose it correctly upon first notice.

Go over the entire length and breadth of the EVAP system, checking for electrical faults along the way. Make sure to inspect the purge valve connector for any visual signs of corrosion, and look for any loose or damaged wires that might seem okay on first glance. 

Check the purge valve itself, looking for any sort of blockage that might be interfering with performance, whether it be from dirt, debris, cobwebs or engine buildup. 

If a visual inspection like this doesn’t bring up any obvious red flags, then you have to get a little more involved and perform a smoke leakage test. This test involves running the engine while looking for vapor that might be leaking. The vapor has a high UC component, so it can be easily seen by shining a bright light or even a UV light. This can be an easy way to find the source of a leak.

Finally, you can check the purge control valve to make sure it offers the proper amount of resistance, and then check how the valve operated by using the ECM to manually control the valve. 

Common mistakes

This is not a hard code to check, but that doesn’t mean you still can’t make mistakes. The most common mistake people make is not performing any sort of visual inspection or check, and just assuming the purge control valve is defective. This is a mistake because you can spend time, money and energy to try and fix one problem and then come to find out later you really have a damaged wire, or some other issue. 

Another common mistake people make is not verifying the failure and replacing parts, only to find out later that there wasn’t a real problem in the first place, or there was a problem, but the code was wrong. 

How serious is this?

Overall, this code is not very serious, but that doesn’t mean you shouldn’t deal with it if it happens. 

The P0443 code causes the check engine light to go on. This alone will cause a failed emission test, which can be a pain if you live in an area where these tests are required as part of your vehicle inspections.

It also means the fuel vapor system control valve is defective or the circuit to it is not making the connection to the valve. This can lead to a drop in your fuel economy, which over time is going to cost you more money and result in more wear and tear on your vehicle.

What repairs can fix the code?

Depending on the actual cause of the problem, there are different ways to fix this issue.

You can test and replace the purge control valve.

If the wiring is the problem, repair the damaged wiring to the purge control valve and take steps to prevent it from getting damaged again.

You can also replace the purge vent valve.