Mystique V6-153 2.5L DOHC VIN L SFI (1999)
Heated Oxygen Sensor: Description and Operation
PURPOSE
The Heated Exhaust Gas Oxygen Sensor (HO2S) detects the presence of oxygen in the exhaust system and produces a variable voltage according
to the amount of oxygen detected.
OPERATION
How The HO2S Signal Is Affected By Oxygen In The Exhaust
A high concentration of oxygen (lean) in the exhaust produces a low voltage signal of less than 0.4 volts while a low concentration of oxygen
(rich) produces a high voltage signal greater than 0.6 volts. The HO2S generates a voltage between 0.0 and 1.1 volts.
The HO2S Signal and Fuel Control
When operating in closed loop the Powertrain Control Module (PCM) monitors this input and correspondingly changes the duration of the fuel
injection pulse width to achieve an air/fuel ratio of 14.7:1.
The HO2S upstream of the Three Way Catalytic (TWC) converter is used for fuel control, the HO2S downstream of catalytic converter is used for
catalyst testing.
