Joe Westy

My wife has a '99 Prelude SH and it's been throwing code P0131. Primary O2 sensor right? Replaced the sensor and the old one definitely looked a bit burnt. Reset the CPU and a few days later the check engine and ATTS lights came back on. Should I replace the other O2 sensor next or given that code, is it likely something else? Possibly a shot cat? Thanks.

mikksteel

You should find the other code and fix what it's telling you, unless it's throwing the same code as last time.

Joe Westy

So with a fresh Denso primary O2, the car is still throwing code P0131 for the primary sensor. Mechanic is saying the voltage is testing good so he thinks it either has to be the pretty rare and in his opinion doubtful with a Denso, "bad part out of the box" routine, or, even though voltage is testing good and preliminary wiring inspection looks good, a wire problem somewhere, or finally he thought, possibly a bad CPU. We've had good experiences with this shop in the past, fair prices and honest, but on this one it looks like they're asking how we'd like them to proceed here...inspect every inch of wire, or try another sensor, or go for a used or new CPU.

Does anybody have experience with this code still popping after a new primary O2? If so, what did the problem turn out to be? I'm trying to decide on a course of action, but hate to throw money at a CPU and have that not be the source of the problem. Any help would be much appreciated, thanks.

bouckarooo

if the voltage checks out then odds are it is issue with ecu.

minilogoguy18

Could be wiring on the engine harness as well, should inspect everything before replacing any more parts.

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