P0155 1997 ford ranger 3.0

Question

Hi, I have a 1997 ford ranger with a 3.0 V6. I have a code P0155 that will not go away. I have checked and changed all Ho2 sensors, I checked for my power and ground with key on to the heater circuit and found that with both bank 1 and bank 2 Ho2 sensors before the cat unplugged I have both power and ground, however when I plug one of those sensors in my ground converts two battery power +. So that gives me two positives and no ground. my question is , is this normal or do I have a pcm problem?

Answer 1

Yes it is its the PCM that gives ground, this is what turns the heater circuit on. so that should be a ground for the heater circuit if it is working properly with the key on.