Technical Description
The O2 Oxygen Sensor Circuit is experiencing high voltage in Bank 1, Sensor 2.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles. While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The Heated Oxygen Sensor (2) located at the rear of the catalytic converter produces an output signal that is relative to the oxygen storage capacity of the catalytic converter. Bank 1 refers to the side of the engine that contains the #1 cylinder.
The Ho2S 2 signal is less active compared to the signal produced by the front oxygen sensor. This code is triggered when the HO2 Sensor voltage exceeds 999 mV for more than 2 minutes (the exact time may vary depending on the model, potentially up to 4 minutes).
Symptoms
There may not be any noticeable symptoms except for the illumination of the MIL (Malfunction Indicator Lamp). It is possible for high fuel pressure to cause the system to become overly rich.
Causes
A code P0138 may indicate one or more of the following:
Possible Solutions
Here are some potential solutions:
