Hi: I have a 2000 4Runner,3rz, 5sp with the Cali emissions pkg. I keep getting a P 0401 (egr insufficient flow) code. The engine runs just fine. I replaced the egr valve and egr gas temp sensor. I get 5v across the sensor plug. Vaccum to the egr valve causes rough idle. I put a 10 ohm resistor in the erg temp sensor plug and my check engine light still comes on (same code). I bypassed the vsv and modulator and ran vaccum directly from the throttle body to the egr valve and I still get the 0401 code. I've cleared the codes after every procedure with my Actron reader and or taking off the (-) battery terminal. I'm thinking that it's the ecm but as long as the engine is running fine I don't want to spend $1200 bucks for a new one. Anyone have any ideas? Thanks, Brian

ps: I just check my mpg's and it's down a bit from 20-21 to under 17

pps: I realized the mileage isn't too far off once I recalculated for the 17" Tacoma wheels that were recently put on. I talked to a local mechanic. He suggested that there might be carbon build up where the exhaust gas dumps into the intake. I took the temp sensor out, sprayed in some Gumout, I started the engine with the sensor out and it ran like it had a big vacuum leak. I killed the light but it came back on. Any help would be appreciated.

 

Follow what the fsm says about correcting this code, and also on the modulator if you blow air though the bottom and it goes though it your modulator is defective.

 

Thanks for the reply: I think that I have gone through everything that the fsm would say to do. Can you suggest anything that I might have missed. I bypassed the modulator by running vacuum directly to the egr. I would have thought that this would trigger a 0402 code for excessive egr flow.

 

This is what i followed when i fixed my CEL
http://forum.ih8mud.com/80-series-te...ml#post1535318
hopefully it works for you too.

 

Thanks for the link. I glanced at it yesterday. I'll look at it this weekend when I have more time to cogitate (after I finish all my honeydews, of course).

 

I finally got a chance to mess with this thing. The problem turned out to be the modulator. I tested it by blowing through the bottom hole, as described by the instructions in the link. I've driven it for 2 days now and the light has stayed off. Thanks, Brian

 

Np glad to help