EGR system used on an 1994 Toyota 4runner with 22RE engine.

Found this video to be very informative. Was not exactly sure how the PQR lines on the modulator worked until I watched this.

 

Meh. There's 17 minutes of my life I won't get back.

The presenter, alas, is pretty confused. He says that the result of a malfunctioning EGR system will give a code P401, but that's an OBD II code, and his vehicle is 2 years too old for that. Instead, it throws code 71 -- IF you have the California vehicle (he was confused by the under-hood sticker. The significant difference with California vehicles is the EGR gas temp sensor, which is what triggers code 71. Only California vehicles have it, so that's how you tell.)

The layout of the 3VZE EGR system is very different from that of the 22re (the operation of the modulator is, mostly, functionally, the same, but you couldn't tell that from the video.)

The VSV he used to demonstrate his "test" is NOT the type of VSV used in the EGR circuit (for California 22re and ALL 3VZE), and the test he tried wouldn't work on an EGR VSV.

His discussion of the operation of the vacuum modulator is sketchy and very limited. Fortunately, you don't have to rely on his failure to read his FSM; you can read it yourself. http://web.archive.org/web/201108151...18egrsyste.pdf The FSM provides a systematic step-by-step diagnosis procedure that covers ALL possible failures, of the EGR valve, the EGR vacuum modulator, the VSV, and the EGR gas temp sensor.

 

Yeah I don't know where he got that code from. Must be a bad edit.

He said it was not California, and pointed out it was a TVV valve.

Difference of opinion here, but his explanation of the modulator turned on the light for me. I can read a FSM until I am blue in the face, and do all the tests to the book, but that does not mean I understand how it all works together.

 

If it helped you, it could help someone else. Thanks for posting it.

This won't, of course, be the first YouTube video that spreads, well, misinformation. I just don't want someone to get stuck following this partial testing procedure, when the real manual is just a click away.