Having an issue with a 01 Civic. Its throwing a CEL the codes are P0420 Cat Efficiency below threshold and p0132 02 Sensor bank 1 Sensor 1 high voltage. Im thinking that the o2 sensor is the culprit and that the P0420 is just because of the O2 being bad. I just want to make sure before i replace the o2 to find out that the cat is bad.

 

LX / DX .. or EX ?

Reset the ECU. (disconnect the battery, or pull fuse number 6 from the under-hood fuse box)

Start the engine and hold it at 3,000RPM (in park or neutral) until the radiator fan comes on.

Check the O2 sensor output voltage.

Is there .9 volts or more?

 

It is an EX

 

Okay, that'll help a little with the next step. But first, do what I had already posted. Then we'll move from there.

 

i have an EX and my car is throwing the exact same code on bank 1 more than likely its gone bad but def replace it im working on doing the same