Oxygen sensors and CEL

1998 Mercury Sable: over 170K miles. CEL came on. mechanic has replaced oxygen snrs. in front of cat.conv.

CEL continues to come on.

he replaced one of the two snrs he had just repl.

any help, experience, thoughts?


The CEL code that points to a bad sensor could also be pointing to a problem in the sensor circuit. If the sensor checks out fine, then there is a problem with the wire. Basically, the computer is getting no signal.

Well, we need to know what codes are being set first off. Drop by a local AutoZone, Checkers, Advance, etc. and have them pull the codes. They will do this for you free. Post any results back here for further discussion.

just out of curiosity… has the catalytic converter itself ever been replaced?

The code should be like P0123