General Information

P0138 O2 Sensor Circuit High Voltage (Sensor 2)

General Information

Component Location





General Description

HO2S (B1/S2) is in the rear side of Catalytic Converter to check the proper operation of catalyst. Oxygen density after the catalytic converter has to be within specific range (around 0.5 V when there is no acceleration and deceleration.)
If the oxygen density changes in accordance with HO2S (B1/S1), it means the poor performance of catalytic converter.

DTC Description

If the sensor output is over 1.08 V under enable conditions, ECM sets DTC P0138.
(This DTC might be caused by the malfunction of Heater circuit, so, check the heater circuit first.)

DTC Detecting Condition





** B1S1 : upstream oxygen sensor / B1S2 : downstream oxygen sensor

Specification





Schematic Diagram





Signal Waveform