One of many extra widespread codes that I sometimes see on a 1997-2001 Toyota 2.2L 4-cylinder Camry is a P0401. It’s a code that signifies that there’s a downside with the EGR System, not essentially an issue the EGR valve itself. I hear tales of individuals pulling getting this code and changing the EGR Valve with out doing any testing as a result of they do not know what to check. They spend useless cash and nonetheless have not mounted the issue.
There are three components that can usually make this code seem in your automobile. Sure the EGR Valve is one among them, however you even have the EGR VSV, and the EGR Modulator. The primary components of inspection will likely be to examine the operate of the EGR Valve by pulling a vacuum on it with a vacuum pump. You will get a vacuum pump at and auto components retailer for round $20 and even hire one at some shops.
Hook up the pump to the one vacuum port in your EGR valve. There will likely be a small hose hooked up, that you will want to disconnect and set up your pump onto the identical port. With the engine working at an idle you need to be capable to pump the vacuum pump to create vacuum on the EGR valve. The diaphragm contained in the EGR Valve ought to increase and trigger the automobile to die. In case your automobile does die then your EGR Valve and it is ports are superb. In case your automobile stumbles or would not have any change in the best way it runs whenever you’re pulling vacuum then you definitely most likely have a nasty EGR Valve or a clogged port in your consumption.
If you happen to suppose you’ve gotten a nasty valve then you need to take it off the engine and take a look at it with the identical vacuum pump. You must be capable to see the diaphragm contained in the valve transfer as you’re making use of vacuum. If the diaphragm does transfer then you could have clogged ports in your consumption and should have to have the consumption cleaned. If it would not transfer then you need to substitute the EGR Valve.
Nonetheless, in case your Camry stopped working whenever you utilized that first vacuum then you need to begin seeking to the EGR VSV. I do know VS what? It is a small blue solenoid situated on the again of the engine block. It is going to have a few vacuum hoses, and a small plug hooked up all be held up there with one 10-mm bolt. Take away the VSV and take a look at it by making use of energy and floor out of your vehicles battery (VSV shouldn’t be plugged into harness when testing.) If you happen to hear the VSV click on whenever you apply energy then you need to substitute the EGR Modulator.
The EGR Modulator is situated to the best of the EGR Valve above your consumption. It is going to have a number of vacuum hoses coming off of it and slides right into a holder. The EGR Modulator could be bought comparatively low cost at your seller. There isn’t any straightforward testing for the modulator. If you happen to substitute the modulator and nonetheless have an issue and the sunshine comes again on, you need to then substitute the EGR VSV also referred to as the Vacuum Switching Valve. Typically the VSV can have an inner break and nonetheless click on whenever you put energy and floor to the terminals, however nonetheless be dangerous.
So you possibly can be losing your cash by simply throwing on a valve. Bear in mind the one approach to repair one thing proper is to know the correct testing process so you’ll be able to come to an accurate repair.