P0401 '00 Camry
 

Hey everyone! I have a '00 Camry 2.2L and the P0401 code keeps popping back up. The car has right at 200k miles on it, but still drives great...so I plan on keeping it going for quite a while. I've replaced the EGR valve and I replaced, what I thought was the, VSV switch. From the researching I've been doing, everywhere says the VSV switch is located on the back of the engine. The switch I replaced is located on the air box lid. It has a plug connector, vacuum line nipple, and a nipple that goes into the air box lid. Is that not the VSV for the EGR system? Should I try taking the actual intake off and cleaning it out next? Anybody with some ideas would be great to hear from. Need some input. Thanks in advance!

You might have replaced the VSV for the EVAP system.

The engine has several VSV's.

The EGR system design changes over time thus the following may not be totally accurate.

Typically the VSV for EGR has two hose connections and what looks like an air filter on one end of the switch. This filter is a vent for one hose when the switch is off.

Find the EGR valve and follow the small rubber hose to what may be the VSV. If not find the EGR modulator (looks like can) and follow any rubber hoses attached to it.

The VSV switch has to be on one of these hoses. It may be mounted in front of the engine above the exhaust manifold and about inline with the engine oil filter.

The VSV can be tested by applying 12V. The switch turns vacuum to the EGR system on/off. When off, engine intake vacuum to the switch is shut off and the hose going from the switch to the EGR system is vented to atmosphere by the switch.

Thanks for the response toyomoho! I guess I did replace the VSV for the EVAP. What confuses me even more is, when I went to Advance Auto to buy the VSV switch, they looked it up for the EGR system. Maybe we were all confused. When my wife gets home from work, I'll have to take a look at it and see if I can find what you were describing to me. I've got to figure it out pretty soon, as her car is due for an inspection this month. Thanks again, and I'll post back what I find.