P0138 O2 Oxygen Sensor Circuit High (B1S2)

Description and meaning of DTC 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 anoutput signal relative to oxygen storage capacity of catalytic converter. Bank 1 is the side of the engine that contains the #1 cylinder. Ho2S2 signal is less active than signal produced by front oxygen sensor. This codesets 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)

p0138 diagnostic trouble code symptoms

There may be no noticeable symptoms except for MIL illumination. Possible highfuel pressure can over rich the system.

DTC p0138 - possible causes

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

How to fix OBD-II diagnostic trouble code p0138

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

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