Ford oxygen sensor
Last Updated on July 30, 2024 by Mutiara
These have been given many names, but all identify the same item on the engine:
- Oxygen Sensor (O2) or (O2S) or (O2’s)
- Exhaust Gas Oxygen Sensor (EGO)
- Heated Oxygen Sensor (HO2)
- Heated Exhaust Gas Oxygen Sensor (HEGOS)
Not all Oxygen sensors are heated, so using the word “heated” might not be correct for certain vehicle applications.
What is a “Rich Mixture,” “Ideal Mixture,” and a “Lean Mixture” all depends on what context it’s used in. The ideal mixture is the amount of fuel needed to make an engine perform as commanded. A rich mixture is when there is more fuel than needed, and lean mixture is not enough fuel.
The HEGO Sensor detects the presence of oxygen in the exhaust and produces a variable voltage according to the amount of oxygen detected. A high concentration of oxygen (lean air/fuel ratio) in the exhaust produces a low voltage signal less than 0.4 volts. A low concentration of oxygen (rich air/fuel ratio) produces a high voltage signal greater than 0.6 volts. The 02 provides feedback to the computer (EEC) indicating air/fuel ratio in order to achieve a near stoichiometric air/fuel ratio of 14.7:1 during closed loop engine operation. The 02 generates a voltage between 0.0 and 1.1 volts.
| Diagnostic Trouble Code (DTC) | HEGO Location | Fault Definition |
|---|---|---|
| 172 / 41 KOER | Right or Rear | HEGO sensor indicates system lean. |
| 136 / 91 KOER | Left or Front | HEGO sensor indicates system lean. |
| 176 CM | Left or Front | HEGO sensor indicates system lean. |
| 173 / 42 KOER | Right or Rear | HEGO sensor indicates system rich. |
| 137 / 92 KOER | Left or Front | HEGO sensor indicates system rich. |
| 177 CM | Left or Front | HEGO sensor indicates system rich. |
| 144 / 41 CM | Right or Rear | No HEGO sensor switching detected or disconnected. |
| 139 / 91 CM | Left or Front | No HEGO sensor switching detected or disconnected. |
| 171 CM | Right or Rear | Adaptive Fuel Limit reached. |
| 175 CM | Left or Front | Adaptive Fuel Limit reached. |
Article & images courtesy of fordfuelinjection.com.
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