Tried the 'quick fix' for a P0420 code on a 2012 Civic and made it worse

Had a customer come in with a P0420, and against my better judgment, I tried one of those 'cataclean' fuel additives they insisted on buying. Ran it through a full tank like the bottle said. Not only did the code not clear, but the downstream O2 sensor reading went completely flat, like it died. Now I'm looking at a new sensor on top of the original converter issue. Anyone else had a snake oil product totally backfire like that?

3 comments

3 Comments

the_jason23d ago

Saw a forum post where a guy used a cleaner and it gummed up the sensor with residue. Those additives can sometimes dislodge gunk that just moves to a worse spot. It's a real gamble that rarely pays off.

ward.tyler23d ago

Yeah the "gamble that rarely pays off" part is where I disagree. I've used cleaners for years on old throttle bodies and MAF sensors. The key is using the right stuff, like the CRC sprays, and letting it dry completely. That residue issue usually happens when people spray it on and rush to start the car. Follow the directions and it works most of the time.

adam_wood9716d ago

Man that's rough, those miracle in a bottle fixes are such a trap lol. Seen it happen before where they just kill a sensor that was barely hanging on.