Scan Tool Testing and Procedures

Troubleshooting of electronic control systems for which the scan tool can be used follows the basic outline described below. Even in systems for which the scan tool cannot be used, part of these systems still follow this outline.

TROUBLESHOOTING CONTENTS

1. STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Troubleshooting strategy are shown.

2. SYSTEM OPERATION AND SYMPTOM VERIFICATION TESTS
If verification of the symptoms is difficult, procedures for checking operation and verifying symptoms are shown.

3. DIAGNOSTIC FUNCTION
The following trouble code diagnosis are shown.
- How to read diagnostic trouble code (DTC)
- How to erase DTC
- Input inspection service points

4. DTC CHART

5. SYMPTOM CHART
If there are symptoms, even though the results of inspection using the scan tool show that all DTC are normal, inspection procedures for each symptom will be found by using this chart.

6. DTC PROCEDURES
Indicates the inspection procedures corresponding to each DTC.

7. SYMPTOM PROCEDURES
Indicates the inspection procedures corresponding to each symptoms classified in the Symptom Chart.

8. SERVICE DATA REFERENCE TABLE
Inspection items and normal judgement values have been provided in this chart as reference information.

9. CHECK AT ECU TERMINALS
Terminal numbers for the ECU connectors, inspection items and standard values have been provided in this chart as reference information.

Terminal Voltage Checks
1. Connect a needle-nosed wire probe to a voltmeter probe.

CAUTION: Short-circuiting the positive (+) probe between a connector terminal and ground could damage the vehicle wiring, the sensor, the ECU, or all three. Use care to prevent this.

2. Insert the needle-nosed wire probe into each of the ECU connector terminals from the wire side, and measure the voltage while referring to the check chart.

NOTE: Measure voltage with the ECU connectors connected.
You may find it convenient to pull out the ECU to make it easier to reach the connector terminals. Checks don't have to be carried out in the order given in the chart.

3. If voltage readings differ from normal condition values, check related sensors, actuators, and wiring, then replace or repair.
4. After repair or replacement, recheck with the voltmeter to confirm that the repair has corrected the problem.

Terminal Resistance and Continuity Checks
1. Turn the ignition switch to "OFF" position.
2. Disconnect the ECU connector.

CAUTION:: If resistance and continuity checks are performed on the wrong terminals, damage to the vehicle wiring, sensors, ECU, and/or ohmmeter may occur. Use care to prevent this!

3. Measure the resistance and check for continuity between the terminals of the ECU harness-side connector while referring to the check chart.

NOTE: Checks don't have to be carried out in the order given in the chart.

4. If the ohmmeter shows any deviation from the Normal Condition value, check the corresponding sensor, actuator and related electrical wiring, then repair or replace.
5. After repair or replacement, recheck with the ohmmeter to confirm that the repair has corrected the problem.

10. INSPECTION PROCEDURES USING AN OSCILLOSCOPE
When there are inspection procedures using an oscilloscope, these are listed here.