B2300 SE Regular Cab 2WD L4-2.3L VIN A (1997)
Oxygen Sensor: Description and Operation
HEATED OXYGEN SENSOR (HO2S)
Detects oxygen in exhaust mixture and outputs a variable voltage to PCM. PCM uses inputs from upstream HO2S to fine tune air/fuel ratio by
controlling required fuel injector pulse width.
NOTE: Downstream sensors are monitors for normal switches.
HO2S produces a variable voltage at a HO2S top temperature of 350°C (662°F) as follows:
-
High concentration of oxygen: less than 0.4 volt
-
Low concentration of oxygen: greater than 0.6 volt
NOTE: No interchangeability between upstream HO2S (green connector) and downstream HO2S (blue connector).
HO2S identification is as follows:
-
Upstream HO2S on #1 cylinder bank: HO2S 1/1
-
Upstream HO2S on opposite bank: HO2S 2/1
-
Downstream HO2S: HO2S 1/2
NOTE: If a heated oxygen sensor or circuit has an open or short, Diagnostic Trouble Code No. P0131, P0133, P0135, P0136, P0141, P0151, P0153
or P0155 is output and poor fuel economy may occur.
