Engine Code PO420
#1
Engine Code PO420
My '99 Suburban 5.7 L with 135k miles keeps giving me a PO420 error code. I have changed all the O2 sensors; the light was reset and stayed out about 1000 miles and then came back on. I swapped sides for the sensors to rule out a bad sensor and it came back on after about 500 miles. I find it hard to believ that the catalytic converter is bad and only on the one side.
Anybody have any other ideas?
Anybody have any other ideas?
#3
RE: Engine Code PO420
well i know a way to fix it but i wouldnt say that it is legal but it is most likely your cats the only other thing it could be is a leak in the exhaust after the first o2 sensor and before the second.
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