Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Readiness monitor drive pattern / Oxygen sensor monitor (front and rear o2s system)
Toyota Corolla (E120): Oxygen sensor monitor (front and rear o2s system)

- Preconditions
The monitor will not run unless:
- mil is off
- drive pattern
- connect the obd ii scan tool to the dlc3 to check monitor status and preconditions.
- Start the engine and allow it to idle for 2 minutes or more.
- Drive the vehicle at 25 mph (40 km/h) or more for at least 50 seconds.
- Stop the vehicle and allow the engine to idle for 40 seconds or more.
- Perform steps (3) and (4) ten times.
- If the readiness status dose not switch to complete, make sure that the preconditions are met and the ignition switch is turned off and then repeat steps (1) through (5).
Other materials:
Hood
Release the lock from the inside of the vehicle to open the hood.
1 Pull the hood lock release lever.
The hood will pop up slightly.
2 Pull up the auxiliary catch lever and lift the hood.
3 Hold the hood open by inserting the support rod into the slot.
CAUTION
■Pre-driving check
C ...
Inspection procedure
1 Reconfirm dtc
Check the dtc
2 Inspect skid control ecu connector securely connected
3 Inspect skid control ecu connector(ig1 terminal voltage)
In case of using hand–held tester:
check the voltage condition output from the ecu displayed on the
hand–held tester.
O ...
Circuit description
The rear heated oxygen sensor is used to monitor oxygen concentration in the
exhaust gas. For optimum
catalytic converter operation, the air fuel mixture must be maintained near the
ideal ”stoichiometric” ratio.
The heated oxygen sensor output voltage changes suddenly in the vicinity of ...


