Toyota Corolla (E120) 2002–2008 Repair Manual / Introduction / How to troubleshoot ecu controlled
systems / Customer problem analysis
Toyota Corolla (E120): Customer problem analysis
Hint
:
- in troubleshooting, the problem symptoms must be confirmed accurately, meaning that all preconceptions must be set aside in order to make an accurate judgement. To ascertain what the problem symptoms are, it is extremely important to ask the customer about the problem and conditions when it occurred.
- The following 5 items are important points in the problem analysis. Past problems which are thought to be unrelated and the repair history, etc. May also help in some cases. Therefore, as much information as possible should be gathered and its relationship with the problem symptoms should be correctly ascertained for use as reference in troubleshooting. A customer problem analysis table is provided for your use in the diagnostics section for each system.
(Sample) supplemental restraint system check sheet.
Other materials:
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 ...
Changing engine switch modes
Modes can be changed by pressing the engine switch with the brake pedal (continuously
variable transmission) or clutch pedal (manual transmission) released. (The mode
changes each time the switch is pressed.)
► Vehicles without a multi-information display
Off*
The emergency flashers ca ...
Circuit description
The purpose of this circuit is to prevent the engine from stalling while
driving in lock–up condition, when
brakes are suddenly applied.
When the brake pedal is depressed, this switch sends a signals to the ecm. Then
the ecm cancels the operation
of the lock–up clutch while braking is i ...