OBD Code P0138

O2 Sensor Circuit High Voltage

What’s mean?

OBD2 Code P0138 Definition:
The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. 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)

Symptoms

Possible sumptoms of P0138
There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.

Possible Causes

Possible causes of P0138
A code P0138 may mean that one or more of the following has happened: Faulty O2 sensor Short to battery voltage in O2 sensor signal circuit High fuel pressure (not as likely)

Possible Solutions

Here are some potential solutions: Replace O2 sensor Repair short to battery voltage in o2 sensor signal circuit