Monitor Description

The heated oxygen sensor generates waveform of a voltage between 0 V and 1 V in response to the oxygen concentration in the exhaust gas. When the output voltage of the heated oxygen sensor is 0.5 V or more, the ECM judges that the air-fuel ratio is RICH. When it is 0.4 V or less, the ECM judges that the air-fuel ratio is LEAN.

If the rear heated oxygen sensor output does not change between RICH and LEAN during "Stop and Go"* driving, the ECM interprets this as a malfunction in the rear heated oxygen sensor and sets a DTC. Also, when the ECM monitors the heated oxygen sensor for 290 seconds (while air-fuel feedback is being performed) and the rear heated oxygen sensor's output remains at 0.05 V or more for 130 seconds, the ECM will determine this as a fault.

HINT:

*: "Stop" indicates a vehicle speed of 0 km/h (0 mph). "Go" indicates a vehicle speed of 30 km/h (18.6 mph).