Abnormal Voltage Output of HO Sensor DTCs P and P

While the ECM is performing active air-fuel ratio control, the air-fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the HO2 sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136 and P0156.

HO2 SENSOR CIRCUIT MALFUNCTION (P0136 and P0156: ABNORMAL VOLTAGE)

15 to 20 seconds

Active air fuel ratio control

HO2 sensor voltage

Operation

Operation

^—\ ''—\ --^-1-

Normal

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Abnormal

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