Just one of the far more prevalent codes that I normally see on a 1997-2001 Toyota 2.2L 4-cylinder Camry is a P0401. It is a code that signifies that there is a trouble with the EGR Method, not always a issue the EGR valve by itself. I hear tales of individuals pulling having this code and replacing the EGR Valve with out accomplishing any testing because they will not know what to test. They invest useless money and nevertheless haven’t fastened the problem.
There are three sections that will usually make this code surface on your vehicle. Certainly the EGR Valve is a single of them, but you also have the EGR VSV, and the EGR Modulator. The to start with components of inspection will be to check the operate of the EGR Valve by pulling a vacuum on it with a vacuum pump. You can get a vacuum pump at and vehicle parts retail outlet for all around $20 and even lease just one at some merchants.
Hook up the pump to the only vacuum port on your EGR valve. There will be a modest hose hooked up, that you will need to have to disconnect and install your pump on to the similar port. With the motor managing at an idle you need to be able to pump the vacuum pump to generate vacuum on the EGR valve. The diaphragm inside the EGR Valve need to increase and result in the motor vehicle to die. If your auto does die then your EGR Valve and it is really ports are fantastic. If your automobile stumbles or does not have any transform in the way it operates when you might be pulling vacuum then you likely have a undesirable EGR Valve or a clogged port in your ingestion.
If you consider you have a bad valve then you should really choose it off the engine and exam it with the exact vacuum pump. You need to be able to see the diaphragm inside of the valve transfer as you are applying vacuum. If the diaphragm does shift then you might have clogged ports in your consumption and may possibly need to have the intake cleaned. If it will not shift then you should change the EGR Valve.
Having said that, if your Camry stopped working when you utilized that first vacuum then you really should start seeking to the EGR VSV. I know VS what? It can be a compact blue solenoid located on the again of the engine block. It will have a few of vacuum hoses, and a small plug attached all be held up there with one 10-mm bolt. Get rid of the VSV and exam it by applying electrical power and floor from your automobiles battery (VSV should really not be plugged into harness when testing.) If you hear the VSV click when you apply electrical power then you should replace the EGR Modulator.
The EGR Modulator is located to the correct of the EGR Valve higher than your ingestion. It will have a number of vacuum hoses coming off of it and slides into a holder. The EGR Modulator can be procured rather low cost at your seller. There is no quick tests for the modulator. If you switch the modulator and however have a dilemma and the light arrives back again on, you must then switch the EGR VSV also known as the Vacuum Switching Valve. Occasionally the VSV can have an inside split and continue to click when you set energy and ground to the terminals, but nonetheless be terrible.
So you could be wasting your revenue by just throwing on a valve. Try to remember the only way to deal with a thing proper is to know the proper testing technique so you can occur to a accurate fix.