The heated oxygen sensor 1 is placed into the front tube. It detects
the amount of oxygen in the exhaust gas compared to the outside
air. The heated oxygen sensor 1 has a closed-end tube made of
ceramic zirconia. The zirconia generates voltage from approxi-
mately 1V in richer conditions to 0V in leaner conditions. The
heated oxygen sensor 1 signal is sent to the ECM. The ECM
adjusts the injection pulse duration to achieve the ideal air-fuel
ratio. The ideal air-fuel ratio occurs near the radical change from
1V to 0V.
CONSULT-II Reference Value in Data Monitor
Specification data are reference values.
Engine: After warming up
Maintaining engine speed at 2,000
0 - 0.3V
Approx. 0.6 - 1.0V
Changes more than 5 times during
On Board Diagnosis Logic
Under the condition in which the heated oxygen sensor 1 signal is
not input, the ECM circuits will read a continuous approximately
0.3V. Therefore, for this diagnosis, the time that output voltage is
within 200 to 400 mV range is monitored, and the diagnosis checks
that this time is not inordinately long.
DTC P0134, P0154 HO2S1