Hi, I am going to install a heated O2 sensor to get my car to get my car to stay in closed loop at idle and while driving. Does the ECM refer to the Oxygen Sensor when its heated up? at a certain speed or RPM? Does the ECM ignore the Heated O2 at any point? THX

 

The ECM looks at the output of the sensor. The ECM applies a high impedance 450mV bias voltage to the sensor. When the sensor is cold, the impedance is high, so the ECM reads 450mV. When the sensor warms up, the impedance is low, and the sensor generates voltage, which overpowers the bias voltage. When the sensor sees lean exhaust (sees O2 in the exhaust), the voltage is very low (because there is O2 on both sides of the sensor, which is how the sensor works). If the sensor sees rich exhaust (sees no O2 in the exhuast), the voltage goes up towards about 1V max.

The sensor is ignored during wide open throttle (actually above about 60% throttle). Also ignored during the first minute or two of engine operation (depending on startup temperature). Also ignored if the signal never goes away from 450 mV +/- 150 mV (i.e. cold, or disconnected). Also ignored if engine temperature is lower than a threshold (about 105F). Also ignored during fuel cutoff.

 

Hi, thanks for the reply.
So I can safely assume that during idle and even slow driving my heated O2 sensor will keep it in closed loop?
THX