Toyota Corolla Repair Manual: Circuit description

Refer to dtc p0130

Hint

: sensor 1 refers to the sensor closest to the engine assembly.

Monitor description

The engine control module (ecm) uses the heated oxygen sensor information to regulate the air–fuel ratio close to a stoichiometric ratio. This maximizes the catalytic converter’s ability to purify the exhaust gases.

The sensor detects oxygen levels in the exhaust gas and sends this signal to the ecm.

The inner surface of the sensor element is exposed to the outside air. The outer surface of the sensor element is exposed to the exhaust gas. The sensor element is made of the platinum coated zirconia and includes an integrated heating element. The heated oxygen sensor has the characteristic whereby its output voltage change suddenly in the vicinity of the stoichiometric air–fuel ratio. The heated oxygen sensor generates waveform of a voltage between 0 v and 1 v in response to the oxygen concentration in exhaust gas.

When the output voltage of the heated oxygen sensor is 0.55 V or more, the ecm judges that the air–fuel ratio is rich. When it is 0.40 V or less, the ecm judges that the air–fuel ratio is lean.

The ecm monitors the response feature of the heated oxygen sensor. If the response time of the sensor output status change from rich to lean or vice versa becomes longer, the ecm interprets this as a malfunction in the heated oxygen sensor and sets a dtc.

Monitor strategy

Typical enabling condition

Typical malfunction thresholds

Component operating range

Wiring diagram

Refer to dtc p0130