The HO2S is used to supply the PCM with information regarding the composition of the air/fuel mixture. The HO2S is positioned in the exhaust pipe ahead of the TWC. To measure the oxygen content, the HO2S requires a supply of ambient air as a reference. Since this is supplied through the wiring, the lead must not be clamped or damaged in any other way. The HO2S produces a voltage that varies between 0.1V and 0.9V under normal operating conditions. The Engine Control Module (PCM) monitors this voltage and determines if the exhaust gas is lean or rich. If the voltage input at the PCM is under approx. 0.45V the exhaust is lean, and if the voltage input is over approx. 0.45V the exhaust is rich. The PCM constantly monitors the HO2S signal during closed loop operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary.
The control unit of the linear oxygen sensor built inside the PCM monitors short circuit errors on all front Heated Oxygen Sensor (HO2S) control lines and the PCM sets P0132 with short circuit to battery.
ITEM | DETECING CONDITION | POSSIBLE CAUSE |
DTC Strategy | ● Sensor voltage high | ● Short to battery in signal harness. ● Contact resistance in connectors. ● Faulty Heated O2 Sensor(HO2S). |
Enable Conditions | ● Sensor preheating and full heating phases finished ● 10V ≤ Battery voltage ≤16V | |
Threshold Value | ● Sensor voltage ＞ 1.3V | |
Diagnostic Time | ● 1 Sec. | |
Fail Safe | ● Reset lambda adaptation and fuel trim adaptation. ● Front HO2S heater is controlled in open loop control. ● EVAP. Emission control function is controlled in minimum operation mode. |
