Grand Voyager V6-3.8L VIN L (1999)
Oxygen Sensor: Description and Operation
HEATED OXYGEN SENSOR (O2S SENSOR)-PCM INPUT
The O2S produce voltages from 0 to 1 volt, depending upon the oxygen content of the exhaust gas in the exhaust manifold. When a large amount
of oxygen is present (caused by a lean air/fuel mixture), the sensors produces a low voltage. When there is a lesser amount present (rich air/fuel
mixture) it produces a higher voltage. By monitoring the oxygen content and converting it to electrical voltage, the sensors act as a rich-lean
switch.
The oxygen sensors are equipped with a heating element that keeps the sensors at proper operating temperature during all operating modes.
Maintaining correct sensor temperature at all times allows the system to enter into closed loop operation sooner. Also, it allows the system to
remain in closed loop operation during periods of extended idle. In Closed Loop operation the PCM monitors the O2S input (along with other
inputs) and adjusts the injector pulse width accordingly. During Open Loop operation the PCM ignores the 02 sensor input. The PCM adjusts
injector pulse width based on preprogrammed (fixed) values and inputs from other sensors.
The Automatic Shutdown (ASD) relay supplies battery voltage to both the upstream and downstream heated oxygen sensors. The oxygen sensors
are equipped with a heating element. The heating elements reduce the time required for the sensors to reach operating temperature.
UPSTREAM HEATED OXYGEN SENSOR
Heated Oxygen Sensor
Heated Oxygen Sensor
