Toyota Corolla (E120) 2002–2008 Repair Manual / Introduction / How to troubleshoot ecu controlled
systems / How to proceed with troubleshooting
Toyota Corolla (E120): How to proceed with troubleshooting
Hint
: carry out troubleshooting in accordance with the procedures on the following page. Here, only the basic procedures are shown. Details are provided in the diagnostics section, showing the most effective methods for each circuit. Confirm the troubleshooting procedures first for the relevant circuit before beginning troubleshooting of that circuit.
1 Vehicle brought to workshop

2 Customer problem analysis
- ask the customer about the conditions and environment when the problem occurred.

- Check the battery positive voltage.
Voltage: 11 – 14 v (engine stopped)
- visually check the wire harness, connectors and fuses for open and short, etc.
- warm up the engine to the normal operating temperature.
- confirm the problem symptoms and conditions, and check for dtcs according to the related chart.
Ok go to step 5

4 Dtc chart
- Check the results obtained in step 3, then confirm the inspection procedures for the system or the part which should be checked using the dtc chart.
Go to step 6
5 Problem symptoms chart
- Check the results obtained in step 3, then confirm the inspection procedures for the system or the part which should be checked using the problem symptoms table.

6 Circuit inspection or parts inspection
- Confirm the circuit for the system or the part which should be checked using the problem symptoms table or the results obtained in step 4.

7 Repair
- Repair the affected system or part in accordance with the instructions in step 6.

8 Confirmation test
- After completing repairs, confirm that the problem has been solved (if the problem does not recur, perform a confirmation test under the same conditions and in the same environment as when it occurred for the first time).

End
Other materials:
Inspection procedure
Hand–held tester:
1 Check operation of stop light
Check if the stop lights go on and off normally when the brake pedal is
depressed and released.
2 Inspect stop light switch assy
Check the resistance between the terminals when the
switch is turned on and off.
Standard:
...
If the electronic key does not
operate properly (vehicles with a
smart key system)
If communication between
the electronic key and vehicle
is interrupted or the electronic key cannot
be used because the battery
is depleted, the smart key
system and wireless remote
control cannot be used. In
such cases, the doors can
be opened and the engine
can be started by following
the procedur ...
Locking the doors from the outside without a key
1 Move the inside lock button to the lock position.
2 Close the door.
► Vehicles without a smart key system
The door cannot be locked if either of the front doors is open and the key is in
the engine switch.
► Vehicles with a smart key system
The door cannot be locked if the engin ...


