DTC P0138: O2 Sensor Circuit High Input (Bank 1 Sensor 2): DTC Detecting Condition

DTC Description
ECM sets DTC P0138 if the ECM detects signal voltage higher than the possible range of a properly operating rear heated oxygen sensor (HO2S).
Conditions for Setting the DTC

Fig 1: DTC P0138 Condition Chart
Courtesy of KIA MOTORS AMERICA, INC.