SLX V6-3.2L SOHC (1996)
Oxygen Sensor: Description and Operation
Manual Transmission
CATALYST MONITOR HEATED OXYGEN SENSORS
A three-way catalytic converter is used to control emissions of hydrocarbons (HO), carbon monoxide (CO), and oxides of nitrogen (NOx). The
catalyst within the converter promotes a chemical reaction. This reaction oxidizes the HC and CO present in the exhaust gas and converts them
into harmless water vapor and carbon dioxide. The catalyst also reduces NOx by converting it to nitrogen. The PCM can monitor this process
using the Bank 1 HO2S 2 and the Bank 1 HO2S 3 heated oxygen sensors. The Bank 1 HO2S 2 sensor produces an output signal which indicates
the amount of oxygen present in the exhaust gas entering the three-way catalytic converter. The Bank 1 HO2S 3 sensor produces an output signal
which indicates the oxygen storage capacity of the catalyst. This indicates the catalyst's ability to efficiently convert exhaust gases. If the catalyst is
operating efficiently, the Bank 1 HO2S 2 signal will be more active than the signal produced by the Bank 1 HO2S 2 sensor. The catalyst monitor
sensors operate the same as the fuel control sensors. The Bank 1 HO2S 3 sensor's main function is catalyst monitoring, but it also has a limited
role in fuel control. If the sensor output indicates a voltage either above or below the 450 mV bias voltage for an extended period of time, the
PCM will make a slight adjustment to fuel trim to ensure that fuel delivery is correct for catalyst monitoring.
A problem with the Bank 1 HO2S 2 signal circuit will set DTC P0157, P0158, or P0160 depending on the specific condition. A fault in the heated
oxygen sensor heater element or its ignition feed or ground will result in lower oxygen sensor response. This may cause incorrect catalyst monitor
diagnostic results. A fault in the Bank 1 HO2S 3 heater circuit will cause DTC P0147 to set.
Legend
1. Bank 1 Sensor 1 (Fuel Control)
2. Bank 1 Sensor 2 (Catalyst Monitor)
3. Catalytic Converter
4. Bank 1 Sensor 3 (Catalyst Monitor)
5. Bank 2 Sensor 1 (Fuel Control)
