if the catalytic converters guts were knocked out would this code be normal i have just moved to Texas and they failed it on the inspection. so i need to fix asap.i have replaced the sensor and the EGR valve and the engine light still comes on with the same code after being reset. thanks
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1998 Mazda B2500 Question: p0401 code EGR insuficient.
Answer #1dandd January 17, 2012, 23:40Master
There is back pressure sensing with the EGR system, so a gutted CAT could make a difference. However, the best thing to do is to really inspect the issue.
http://repairpal.com/OBD-II-Code-P0401 here is an article that I wrote that describes how to inspect for a P0401. On a Ford/Mazda ( very close really ) the DPFE or EGR feedback sensor should be carefully checked as well. It has 2 rubber tubes that sense exhaust back pressure ( that is why a hollowed CAT be a problem ) . But don't just buy a CAT, it may be the sensor, a bad valve, a bad vacuum solenoid not opening the valve etc, etc.