Mechanics

CODE: P0401-EGR INSUFFICIENT AIR FLOW

1996 Isuzu Trooper • 6 cylinder 4WD Automatic • 194,000 miles

CODE: 0401 says that I have insufficient airflow in the EGR area. I have had this code for almost a year. I have replaced the EGR valve with a new one, ran a number of different cleaners through the EGR system, cleaned the EGR pipe, checked the EVAP container, checked for bad vacuum hoses and have been saying my prayers. Still the code is there and I now think that maybe it is a bad or intermittent electrical part. Maybe it is the VSV-vacuum switch valve? It is an AC Delco Remy 201. It runs about $20.00. Maybe the ECM is bad in putting out EGR signals? Does anyone have any other ideas? My gas mileage is down to about 10 mpg and I am going through oil like crazy. Thanks.
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Quicksword
April 8, 2011.



That's most likely just a plugged up passage through the intake manifold. There is a passage that runs from the EGR valve itself to the intake manifold somewhere. Most of them narrow down in one spot and that spot build up with carbon and it has to be manually dug out. You may have to remove the throttle body to access it.

Wrenchtech
Apr 8, 2011.
Thanks, my guess has been that it is still a plugged area, I just did not know where it might be, but what you say makes sense.

Tiny
Quicksword
Apr 8, 2011.
You may have to pull off the throttle body to see the hole outlet.

Wrenchtech
Apr 8, 2011.
Super diagrahm- THANKS!

Tiny
Quicksword
Apr 8, 2011.