Pesky 0401
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Pesky 0401
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.
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.
Last edited by blambertpt; 01-30-2012 at 04:16 AM. Reason: additional info
#2
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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.
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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.
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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.
http://forum.ih8mud.com/80-series-te...ml#post1535318
hopefully it works for you too.
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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).
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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
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