Got the codes, now what? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Got the codes, now what?


September 12, 2001
Reaction score
City, State
South Bend, Ind
Year, Model & Trim Level
'96 XLT 4-dr V-6
Went to Autozone with my 1996 V6 to get the codes read. The CEL has been on for about 2 weeks. He pulled two codes:

133: O2 sensor slow response, bank 1, sensor 1
420: catalyst system efficiency below threshhold

He said if the catalyst was plugged, that could cause the O2 sensor code. He didn't know if the O2 sensor problem could cause the catalyst code. Autozone can't test the O2 sensor but apparently it can be tested to see if it's bad or not.

What do you think, gentlemen? BTW, the engine is running fine so whatever it is hasn't affected driveability.

If you haven't noticed any lack in power or driveability, then I'd lean more towards the O2s than the cats. There is a third O2 sensor after the cats, and this can cause the cat code. I'd replace all your O2 sensors. Besides the O2s are cheaper to replace than the cats anyway ;)