1 of the additional widespread codes that I typically see on a 1997-2001 Toyota 2.2L 4-cylinder Camry is a P0401. It is a code that suggests that there is a dilemma with the EGR Program, not always a trouble the EGR valve itself. I listen to tales of people pulling acquiring this code and changing the EGR Valve without the need of carrying out any tests mainly because they will not know what to test. They devote pointless funds and nonetheless have not fixed the challenge.
There are a few parts that will typically make this code appear on your automobile. Sure the EGR Valve is a single of them, but you also have the EGR VSV, and the EGR Modulator. The 1st areas of inspection will be to check the perform of the EGR Valve by pulling a vacuum on it with a vacuum pump. You can get a vacuum pump at and car parts keep for around $20 and even rent a single at some shops.
Hook up the pump to the only vacuum port on your EGR valve. There will be a small hose hooked up, that you will will need to disconnect and install your pump onto the exact port. With the engine operating at an idle you really should be able to pump the vacuum pump to develop vacuum on the EGR valve. The diaphragm within the EGR Valve should increase and trigger the car to die. If your automobile does die then your EGR Valve and it’s ports are great. If your automobile stumbles or won’t have any modify in the way it runs when you happen to be pulling vacuum then you most likely have a lousy EGR Valve or a clogged port in your intake.
If you believe you have a terrible valve then you should just take it off the motor and check it with the exact same vacuum pump. You should be capable to see the diaphragm inside the valve transfer as you are applying vacuum. If the diaphragm does shift then you may have clogged ports in your ingestion and might require to have the consumption cleaned. If it won’t shift then you should substitute the EGR Valve.
Having said that, if your Camry stopped managing when you used that first vacuum then you ought to begin hunting to the EGR VSV. I know VS what? It really is a little blue solenoid found on the again of the motor block. It will have a pair of vacuum hoses, and a compact plug hooked up all be held up there with a single 10-mm bolt. Clear away the VSV and exam it by making use of energy and ground from your autos battery (VSV must not be plugged into harness when screening.) If you hear the VSV click when you apply power then you should really replace the EGR Modulator.
The EGR Modulator is located to the appropriate of the EGR Valve higher than your consumption. It will have numerous vacuum hoses coming off of it and slides into a holder. The EGR Modulator can be bought relatively cheap at your dealer. There is no simple tests for the modulator. If you substitute the modulator and nevertheless have a issue and the light comes back again on, you really should then switch the EGR VSV also recognized as the Vacuum Switching Valve. At times the VSV can have an interior crack and nevertheless click when you put electric power and ground to the terminals, but nonetheless be poor.
So you could be squandering your dollars by just throwing on a valve. Bear in mind the only way to take care of one thing ideal is to know the proper testing technique so you can appear to a proper deal with.
