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:
On–vehicle inspection
1. Inspect w/receiver condenser assy
if a fin of the w/receiver condenser assy is dirty, clean it with
water and dry it with compressor air.
Notice:
do not damage the fin of the w/receiver condenser assy.
if a fin of the w/receiver condenser assy is bent, make it
straig ...
Terminals of ecu
1. Inspect integration relay
Disconnect the connector from the integration relay.
check the continuity between each terminal of the disconnected connector
and the body ground, as
shown in the illustration and table.
Standard:
If the result is not as specified, the vehicle’s ...
Inspection procedure
Hint:
start the inspection from step 1 in case of using the hand–held tester and start
from step 2 in case of not
using the hand–held tester.
1 Read value of hand–held tester(front speed sensor)
Select the datalist mode on the hand–held tester.
check that there is no differe ...