DTC 0420 code?
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Staging Lane
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Join Date: Jan 2003
Location: Central Iowa
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Just got this (DTC 0420) tonight. Says left bank Cat efficency low. Haven't had time to watch left O2's to see if they switch on startup. Is this most likely a bad left rear O2 or is my cat (oh, darn, time for exhaust work) actually taking a dump? Tommorrow on the way to work I'll watch the O2 readings to see what they do.