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
1 Inspect transmission wire(sl)
Disconnect the transmission wire connector from the
transaxle.
measure the resistance according to the value(s) in the
table below.
Standard:
2 Check harness and connector(transmission wire – ecm)
Connect the transmission wire c ...
General information
1. Basic dimensions
(a) there are two types of dimensions in the diagram.
(1) (Three-dimensional distance)
straight-line distance between the centers of two
measuring points.
(2) (Two-dimensional distance)
horizontal distance in forward/rearward direction
between the centers o ...
Hydraulic test
1. Perform hydraulic test
Measure the line pressure.
Notice:
Do the test at normal operation atf temperature 50 to 80 °c (122 to
176 °f).
The line pressure test should always be carried out in pairs. One
technician should observe
the conditions of wheels or wheel stopper outsi ...


