p0401 & p0402
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04-01-2015, 06:06 PM
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#2
04-01-2015, 11:10 PM
Welcome to FTE.
P0401 = EGR insufficient. P0402 = EGR excessive. Seeing as how you have an excessive code along with the insufficient code, it suggests that the EGR valve & the computer operated vacuum switching valve that controls the EGR are working, but getting corrupt commands. So I'd consider putting the DPFE sensor, its exhaust feedback & vacuum hoses, the reference voltage supplied by the computer to the DPFE sensor, the sensors PID output back to the computer being corrupt, high up on your suspect list. A faulty DPFE sensor, or hoses being dry rotted or baked out & cracked, are the most frequent problems.
Some thoughts for consideration, let us know how your trouble shoot goes.
P0401 = EGR insufficient. P0402 = EGR excessive. Seeing as how you have an excessive code along with the insufficient code, it suggests that the EGR valve & the computer operated vacuum switching valve that controls the EGR are working, but getting corrupt commands. So I'd consider putting the DPFE sensor, its exhaust feedback & vacuum hoses, the reference voltage supplied by the computer to the DPFE sensor, the sensors PID output back to the computer being corrupt, high up on your suspect list. A faulty DPFE sensor, or hoses being dry rotted or baked out & cracked, are the most frequent problems.
Some thoughts for consideration, let us know how your trouble shoot goes.
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