One of our work trucks had had multiple codes (P0054, P2270, P0300 and P0306). The truck was running crap. So I did the coil swap diagnosis. Switched #6 with # 7 and the code followed the coil. Put a new coil in and the truck runs normally again and all the codes stayed away except for P0054 which is "HO2S Heater Resistance (Bank 1 Sensor 2)" I figured the two O2 sensor codes were tripping due to the misfire and out of range exhaust values and expected them to clear with the fixed coil. I would think it is less likely a faulty sensor and something more to do with what it is reading but never assume right? Any ideas given this particular circumstance? This is an 05 F150 5.4 with 155 000 miles (250 000 KM)

 

An o2 heater resistance code is one of the few codes that 9 out of 10 times means that sensor is bad. The reason that code is tripped is because the computer can no longer measure the resistance in the heater coil of that o2 sensor. This can be caused by only 2 things, 1. The heater element of the sensor is blown(like a bad light bulb) or 2. The wiring from the PCM to the heating element of the o2 sensor has a break in it. Since it is a downstream o2, it's only purpose in life is to monitor the efficiency of the catalytic converter that it is downstream of and has no effect on the fuel ratio or how the engine performs.

 

Thank you for the good information.