1999 Honda Civic check engine light still on

1999 Honda Civic 4 cyl Two Wheel Drive 125kms miles

code 41 (135) 1- installed new primary oxy sensor, reset system, light still comes on.
2-changed ect sensor, reset system, light still comes on.
3-exchanged new primary oxy sensor at parts store telling them it is a faulty sensor, installed second NEW sensor, reset system, light still comes on!!!
4- HELP.... Mike