Recirculation exaust gas detected code po 401 2.2 camry auto.... switch?

SOURCE: P0401 Exhaust Gas Recirculation Flow Insufficient

check the metal line that comes off the exhaust and make sure it isnt plugged with carbon. also remove the egr and check the port and see it's clogged as well

SOURCE: Check engine light. Code: Exhaust gas

Usually this is due to carbon build up. Fuel injector cleaners will not help. It involves removal of the EGR valve and inspection of the valve for carbon and the passages for carbon. You can also test the valve itself prior to removal if it is vaccuum operated. Unplug the vac hose, plug it and then install a piece of vac hose long enough to reach it without bending over the engine. While the engine is idleing apply vaccuum to the hose via a pump or the old fashioned way via sucking on it and note engine idle change. If none either the baffle is bad inside the valve or it is clogged. Hope this helps.
Also, some EGR valves have a vac control solenoid and those go bad too. If the idle does change via the procedure above then suspect the control vac solenoid.

SOURCE: How do I clean the EGR sensors like the auto zone

The EGR valve is usually not servicable. Just replace it. it works in an ugly environment.

SOURCE: Have a 2000 Chevy Monte

With the EGR valve removed and the engine running you should have a strong vacuum on the intake side and good exhaust flow from the exhaust side. Most of the time the vacuum side is weak and will require cleaning. You will need to remove the throttle body to properly clean the EGR passage. If the passages are clear then check to see if the computer is sending the correct signal to open the valve.

SOURCE: 1998 plymouth breeze: Engine

EGR system failure. The negative battery cable must be removed first. The EGR is the system under the hood, between the fuse box and the block. The TCM Looks kind of like a radiator, and needs to be removed to access the EGR valve. It has two vaccumn hoses connecting it to the vaccuum system, make sure you keep track of where they connect to. Loosena nd removed the bolts holding the EGR, and gently remove the EGR valve.
Remove the old gasket and replace with a new one, install the new EGR and finger tighten the bolts. Make sure the vaccuum hoses are placed back on (label them if needed), once you have ensure that you have everything installed properly, then tighten the bolts on the EGR to 200 ft. lbs. Re-install the TCM and connectors, reconnect teh battery and you should be good to go.