Since we've got several threads related to other CEL codes in the archives, I figured I'd start one for this.
CEL went on last week. I reset it without checking the code.
Came back on again last night, so I went to a local auto parts store to have them pull the code. P0420, which is a catalyst effeciency below threshold.
For those who care, I guess this code gets thrown throught the following scenerio (stolen from the FSM):
Haven't had a chance to check the O2 sensors yet, which the FSM recommends before replacing the cats. I've got a few days before I'll have a chance to hook an ohmeter up to them, so I'm left sitting here and wondering. My question is, has anyone had this code before and had it turn out to be just the O2 sensors?
A search on the forum yeilded this thread and this thread, both over two years old and with no resolution.
I've got almost 125K on my 95, and I'm pretty sure the O2 sensors have never been replaced as I bought it with around 70K on it back in '00. I sent an e-mail to Kansas City Converters to inquire about re-built cats just a few minutes ago, and am waiting to hear what they say.
Figured if nothing else, I'll just sail this one alone and post what happens so that anyone with this code in the future will have a loose guideline to follow.
CEL went on last week. I reset it without checking the code.
Came back on again last night, so I went to a local auto parts store to have them pull the code. P0420, which is a catalyst effeciency below threshold.
For those who care, I guess this code gets thrown throught the following scenerio (stolen from the FSM):
FSM said:Air fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeatedly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the catalyst.
But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated.
Haven't had a chance to check the O2 sensors yet, which the FSM recommends before replacing the cats. I've got a few days before I'll have a chance to hook an ohmeter up to them, so I'm left sitting here and wondering. My question is, has anyone had this code before and had it turn out to be just the O2 sensors?
A search on the forum yeilded this thread and this thread, both over two years old and with no resolution.
I've got almost 125K on my 95, and I'm pretty sure the O2 sensors have never been replaced as I bought it with around 70K on it back in '00. I sent an e-mail to Kansas City Converters to inquire about re-built cats just a few minutes ago, and am waiting to hear what they say.
Figured if nothing else, I'll just sail this one alone and post what happens so that anyone with this code in the future will have a loose guideline to follow.
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