Hello everyone I'm new here and needed help with my car. I broke one of downstream 02 sensors with a lift. I replaced the sensor but I cannot figure out how to turn the check engine light off and it's not running well. Car has headers and a full exhaust.
Just wondering. What model year Mustang are we talking about?
As for how to reset the check engine light a simple battery disconnect should to the trick. Soooooo if the battery has been disconnected but the check engine light still remains on then likely there's still a problem going on.
In general all four O2 sensors share a heater circuit. So a short in one will take out all four. First did you check all of the fuses? Perhaps when the O2 sensor was broken it also shorted out the heater circuit.
There definitely still is a problem. The car is a 2000 mustang gt 4.6 v8. I can not find the fuse for the circuit any help would be appreciated. Some people have said that the ecu controls the o2 on these cars but I don't know if this is true.
Check fuse F2.8 and F2.2 in the Central Junction Box=CJB=F2
Not a bad idea to check all of the fuses in the CJB and engine bay as well.
And yes the PCM does control the heaters on/off by grounding to complete the circuit. But there's still a fuse to protect the entire circuit from burning the car down. One of the Oh by the ways of a ground start circuit is there's always power in the circuit even when the PCM has commanded it off. Sooooooo if the wires are damaged and short to ground, the fuse is the only thing that can protect the circuit.