Rep Power: 0

Hi,
the check engine light is on, the scanner shows a defective O2 sensor #1 heating circuit.
Which is the #1? There is one above and one below the cat converter.
Oh, it is a 1999 DX, 1.5

 
Rep Power: 263

If you disconnect one o2 sensor then rescan see if it says 1 still if 2 comes up then u know u unplugged the wrong one Right now im having a brain fart but im sure theres a easier way to do this
check the 02 sensor wires maybe ones melted or stripped. check the primary o2 sensor usually its that one i think or make sure ur cat isnt the problem tap the cats for rattling

 
Rep Power: 389

bank one is before the cat.

 
Rep Power: 812

yeah its below the header, not the one inside the cat.

 
Rep Power: 389

^ its in the header, above the cat..

 
Rep Power: 812

oops yeah i meant for ex, but he has dx