Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
The voltage that you are seeing may be a bias. According to the diagram that I am looking at, the ECM grounds the sensor and powers the heater control. Do you have good ground to the sensor and good feed to the heater from the ECM? Do you have good ground to the heater circuit? Any codes?
I measured the upstream o2 resistance and it was around 100 ohms so I changed it but still would like to see a 5v on signal wire when it’s unplugged. I mentioned it was 2.5 but actually it is 1.6v.
The return wire has 2.5v. I am trying very hard to find something because i don’t want it to be a bad ecu.
Topic Author
