Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Oxygen sensor circuit no activity detected / Circuit description

Toyota Corolla (E120): Circuit description

Refer to dtc p0130

Dtc no.	Dtc detecting condition	Trouble area
P0134	After engine is warmed up, heated oxygen sensor (bank 1 sensor 1) output does not indicate rich (greater than 0.45 V) even once when conditions (a), (b), (c), (d) and (e) continue for more than 65 seconds (1 trip detection logic) :  engine speed: 1,400 rpm or more  vehicle speed: 24.8 Mph (40 km/h) or more  throttle valve is not fully closed  180 seconds or more after starting engine  engine coolant temperature is more than 40 c (104 f)	Open or short in heated oxygen sensor (bank 1 sensor 1) circuit heated oxygen sensor (bank 1 sensor 1) heated oxygen sensor heater (bank 1 sensor 1) efi relay air induction system fuel pressure pcv hose connection pcv valve and hose injector gas leakage in exhaust system pcv piping ecm

Hint

: after confirming dtc p0134, check the output voltage of the heated oxygen sensor (bank 1 sensor 1) in the ”diagnosis / enhanced obd ii / data list / all” using the hand-held tester or the obd ii scan tool.

If the output voltage of the heated oxygen sensor is always less than 0.1 V, the sensor circuit may be open or short.

Monitor description

The ecm uses the heated oxygen sensor to optimize the air–fuel mixture in the closed–loop fuel control.

This control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture.

The sensor detects the oxygen level in the exhaust gas and the ecm uses this data to control the air–fuel ratio. The sensor output voltage ranges from 0 v to 1 v. If the signal voltage is less than 0.4 V, the air–fuel ratio is lean. If the signal voltage is more than 0.5 V, the air–fuel ratio is rich. If the sensor does not indicate rich even once despite the conditions for the closed–loop fuel control being met and a specified time period has passed, the ecm will conclude that the closed–loop fuel control is malfunctioning. The ecm will illuminate the mil and a dtc is set.

Monitor strategy

Typical enabling condition

Typical malfunction thresholds

Component operating range

Wiring diagram

Refer to dtc p0130