P0155 code on 95 windstar

I have a recurring code problem -it sez its o2 sensor bank 2 sensor 1 but they are all new now. The data stream gives me good values on 3 of them but o2 sensor bank 1 sensor 1 jumps around it and out of tolerance.

I switched sensors from hole to hole in the bank 2 area and no change occurs. reads the same and the MIL lights up first time you restart the engine.

Currently thinking on replacing the PCM .

The engine just had a valve job and tranny rebuilt also.

P0155 = O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1).

Check the O2 heater circuit wiring and connections...they may have been pinched/damaged during the tranny R&R.

Good luck and keep us posted.

circuits give 12 volts reading on heater wires-have not checked amps as of yet. 10 v is minimum

If left for a week I get codes for not switching. It was doing this b4 the tranny job.

Correct me if I'm wrong but I'm thinking the pcm has dumped the drivers for that heater circuit.