The rear heated oxygen sensor is mounted on the rear side of the Catalytic Converter (warm-up catalytic converter) or in the rear exhaust pipe, which detects the catalyst efficiency. The rear heated oxygen sensor (HO2S) produces a voltage between 0V and 1V. This rear heated oxygen sensor is used to estimate the oxygen storage capability. If a catalyst has good conversion properties, the oxygen fluctuations are smoothed by the oxygen storage capacity of the catalyst. If the conversion provided by the catalyst is low due to aging, poisoning or misfiring, then the oxygen fluctuations are similar to signals from the front oxygen sensor.
ECM sets DTC P0136 if the ECM detects that the rear HO2S signal circuit is open.
ITEM | DETECTING CONDITION | POSSIBL ECAUSE |
DTC Strategy | ●Check open circuit on rear HO2S | ● Open in signal harness ● Open in ground harness ● Contact resistance in connectors ● Faulty Heated O2 Sensor(HO2S) |
Enable Condition | ● Sensor preheating and full heating phases finished ● No relevant failure ● 10V〈Battery voltage 〈16V | |
Threshold Value | ● Sensor element resistance 〉 60kΩ | |
Diagnostic Time | ● 11 sec. |
