Toyota Corolla (E120) 2002–2008 Repair Manual / Introduction / How to troubleshoot ecu controlled
systems / Problem symptoms table
Toyota Corolla (E120): Problem symptoms table
The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to troubleshoot the problem when a normal code is displayed in the diagnostic trouble code chart but the problem is still occurring. Numbers in the table indicate the order in which the circuits or parts should be checked.
Hint: when the problem is not detected by the diagnostic system even though the problem symptom is present, it may be that the problem is occurring outside the detection range of the diagnostic system.

Other materials:
Fail–safe chart
If any of the following codes is recorded, the ecm enters the fail–safe mode.
Check for intermittent problems
Hand–held tester only:
by putting the vehicle’s ecm in the check mode, the 1 trip detection logic is
possible instead of the
2 trip detection logic, and the sensitivity to de ...
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 ...
If you think something is wrong
If you notice any of the following
symptoms, your
vehicle probably needs
adjustment or repair. Contact
your Toyota dealer as
soon as possible.
Visible symptoms
Fluid leaks under the vehicle.
(Water dripping from the air
conditioning after use is normal.)
Flat-looking tires or uneven
tire wear
...


