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:
Headlamp dimmer switch assy
Replacement
1. Remove steering column cover lwr
Remove 3 screws and steering column cover lwr.
2. Remove headlamp dimmer switch assy
Disconnect the connector.
release the claw and pull out the head light dimmer
switch assy.
...
Diagnostic trouble code chart
Notice:
when removing the part, turn the ignition switch to off.
Hint:
using sst 09843–18040, it connect the terminal tc and cg of dlc3.
If any abnormality is not found when inspecting parts, inspect the ecu and
ground points for poor contact.
If a malfunction code is displayed during ...
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 ...


