Skylark L4-144 2.4L DOHC VIN T SFI (1997)
Oxygen Sensor: Description and Operation
Oxygen (O2) Sensor
Description
The Oxygen Sensor (O2S 1) is mounted in the exhaust system where it can monitor the oxygen content of the exhaust gas stream. The oxygen content in
the exhaust reacts with the sensor to produce a voltage output.
Operation
This voltage ranges from approximately 0.1 volt (high oxygen - lean mixture) to 0.9 volt (low oxygen - rich mixture). This voltage can be measured with
a scan tool.
By monitoring the voltage output of the 02S 1 the PCM will know what fuel mixture command to give to the injectors.
-
Lean mixture - low 02S 1 voltage = rich command
-
Rich mixture - high 02S 1 voltage = lean command
Circuit Faults
The 02S 1, if open, should set a Diagnostic Trouble Code (DTC) P0134. A constant low voltage in the sensor circuit should set a DTC P0131. A
constant high voltage in the circuit should set a DTC P0132. DTCs P0131 and P0132 could also be set as a result of fuel system problems. See DTC
tables for conditions that can cause a lean or rich system.
