O2 sensors not reading.

[muddacres]

98 explorer 4.0 SOHC. Not reading O2 sensors and fuel trim. It runs fine. I replaced computer and tried new O2 sensor. The fuse is fine and it has power at the sensor.:scratch::scratch::scratch: HELP
Jim

 

[SoHK_alumni]

Any chance the engine temp sensor never reports the engine is up to temp so the ECU stays in closed loop and ignores the O2 sensors?

 

[1996BLKBauer]

It should still show a reading whether it is on closed, or open loop, you might have an issue with a wire somewhere. Possibly not sending anything to the ECU. Back probe the pin on the ECU from the o2 sensor and see what it is reading, it will obviously vary, but see if you are getting anything.

 

[muddacres]

I pulled the wiring harness out and it checks out fine. While I had it apart I changed the coolant sensor. I took the Explorer back to my buddies shop and the o2 sensors still don't read.:scratch::scratch::scratch:
Jim