O2 Sensor Control

[joefnh]

I am currently having problems with the control/functioning of the bank 2 front O2 sensor.
When running the SCT Pro Racer software I noted that the sensor was not switching. The sensor does respond very slowly to revving the engine or idling by slowly changing from .1Vdc to .8Vdc, but does switch normally as the other 3 sensors do.

I have swapped this sensor twice with the same results. I cannot find information on a fuse or relay that supplies power to the O2 sensors

Any ideas on how to troubleshoot this?

Thanks in advance

--Joe

 

[ExplorerDMB]

It's ONLY when you run the program?

-Drew

 

[joefnh]

Thanks for the reply Drew.

I finally figured out the problem today. While troubleshooting this problem, I had replaced the o2 sensor twice with Bosch sensors purchased at Auto Zone a local car parts store.

Apparantley the 03 Frod Explorer uses 2 types of sensors, a 3.3 ohm and a 6 ohm heater coil type. The 3.3 ohm ones are used in the front or upstream positions while the 6 ohm ones are used after the cats. Auto Zone apprantly did not know this.

In Fords service DVD manual the reason given for this is so that the front sensors can heat up faster (as the 3.3 ohm heater will draw roughly twice the current of the 6 ohm heater) to enable the engine to enter the closed loop mode sooner.

After swithching out the sensor with the correct model it ran fine.

Thanks again

--Joe