I'm having trouble with a 96 5.0 F150, I'm getting Code P0135 which is heater malfunction bank 1 sensor 1. I replaced the sensor and still have the problem. I went to check the votage to the sensor acording to my manual The large red wire should be batt + in start/run and the smaller red/grey wire should be ground. No voltage across them so I gounded my multimeter to the batt and checked again and found 11 volts on both wires. Does this mean that the ground wire has shorted or is the manual wrong. With the truck running and all sensors hooked up I show the normal .3-.5 volts on the other 2 sensors but .07 volts on the sensor in question. Can anyone help me out with this

 

If you have 11v drop between battery+ and the groung wire on the HEGO sensor plug, the ground wire is OK.

If you have 11v between the battery+ and the power supply wire with the ignition in run, then there is a break in the wire or it has worn through the insulation and is grounding somewhere.

 

Well I fixed the short Now the check engine light is off and seems to be staying off, but I'm picking up a pending trouble for the O2 sensor on the other side but as long as the light stays off It should pass inspection. After I replaced that sensor I understand why the previous owner pulled the dash and removed the check engine bulb instead of replacing the sensor what a pain to replace