Originally posted by ethan:
...it read off code 171, as usual, but this time it was accompanied by code 133, which relates to an o2 sensor. i was told where the MAF sensor was and that's how i came to mess with it, but i have virtually no under-hood experience and i don't know where either of the o2 sensors are located. is it possible i could have damaged one while working with the air hose?
...


0133 is also related to MAF for the I4 Zetec 2.0


Per TSB,
Electrical:
�· Shorted/open wiring
�· PCM
Induction System:
�· MAF sensor (On 4-cylinder engines, if P0133 is present, this could be caused by a MAF issue - on 6- and 8-cylinder engines, this could only be a MAF issue if P0133 and P0153 are both present)
�· Inlet air leaks (unmetered air)
Fuel Concerns:
�· Poor fuel quality
Base Engine:
�· Exhaust leaks (upstream or near HO2S)
HO2S Concerns:
�· Contaminated HO2S sensor (contamination from the use of silicone-based cleaners and sealants, leaded fuel, excessive oil consumption, etc.)
�· Deteriorating HO2S sensor

"Always do the cheap and easy ones first." 1996 V6 ATX 96K miles