check engine light on today..code PO420..96 explorer

[porshapower]

Have been chasing a slight rough idle with no luck on my 4.0 1996 explorer. Today the best thing that could of happened finally did..check engine light. Was on my way home...stopped at Autoparts store and they pulled the code of PO420 (catalyst efficiency below threshold BANK 1) Is this the catalytic converter or o2 sensor? Which catalytic converter? Thanks!Nel

 

[jimbo74]

420 is usually the O2 sensor and bank 1 is passenger side

 

[dogfriend]

Hopefully it is the O2 sensor, but this code is supposed to indicate that the catalytic converter is not working - the O2 sensor after the catalytic converter is not sending the correct signal.

 

[raaizin]

I had the same code on my '96. I changed the air/fuel filters which were way beyond their life expectancy. I then cleaned out the IAC valve and it seems to have gone away. I have driven about 10k miles. Seems cheaper than the alternative. I bought an 02 SIM to pass inspection if ned be. From what I read the P0420 codes is USUALLY NOT a bad o2 sensor. Hopefully this is a cure. Ray Good Luck!!

 

[porshapower]

Hollowed out catalytic converter....

Yesterday hollowed out the catalytick converter..was original and a mess..looked like someone poured concrete in both of them. Hollowed out both. Reset check engine light. Drove around for an hour and check engine light back on with same 420 code. Bought the oxygen sensor for bank 1 (passenger side) before the catalytic converter and reset the light again. Drove for about an hour and light appeared again with same code. Went and bought oxygen sensor for after the catalytic converter and installed it. Have driven around all day today with no more check engine light but truck exhaust stinks! Smells like the exhaust of my old 57 chevy. Is this because of a hollow catalytic converter?? Thanks!! Nel

 

[dogfriend]

Have driven around all day today with no more check engine light but truck exhaust stinks! Smells like the exhaust of my old 57 chevy. Is this because of a hollow catalytic converter?? Thanks!! Nel

Yes.

Theoretically, you should still get the P0402 code if your cat is not functioning. The reason that it smells bad is because the cat is supposed to convert HC and NOx, but its not doing anything.

 

[porshapower]

Im going to get an aftermarket cat installed tomorrow.

Cant drive truck like this..it stinks and burns my eyes when I drive! ThanksNelson