Diagnostic Trouble Code
P0138
O2 Oxygen Sensor Circuit High (B1S2)
Technical Description P0138
O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)
What Does This Mean P0138?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model.
The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Bank 1 is the side of the engine that contains the #1 cylinder.
Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)
The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Bank 1 is the side of the engine that contains the #1 cylinder.
Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)
Possible Causes P0138
1
Faulty O2 sensor
2
Short to battery voltage in O2 sensor signal circuit
3
High fuel pressure (not as likely)
Solutions & Repair Steps P0138
Here are some potential solutions: