Toyota Highlander Service Manual: How to proceed with troubleshooting

Toyota Highlander Service Manual / Introduction / How to troubleshoot ecu controlled systems / How to proceed with troubleshooting

HINT: Carry out troubleshooting in accordance with the procedures below. Only a basic procedure is shown. Details in the Diagnostic Section show the most effective methods for each circuit. Confirm the troubleshooting procedures for the relevant circuit before beginning troubleshooting.

1 VEHICLE BROUGHT TO WORKSHOP

2 CUSTOMER PROBLEM ANALYSIS

(a) Ask the customer about the conditions and environment when the problem occurred.

3 SYMPTOM CONFIRMATION AND DTC (AND FREEZE FRAME DATA) CHECK

Check the battery positive voltage.
Standard: 11 to 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.

4 DTC CHART

(a) Check the results obtained in step 3, then confirm the inspection procedures for the system or part using the DTC chart.

5 PROBLEM SYMPTOMS CHART

(a) Check the results obtained in step 3. Confirm the inspection procedures for the system or part using the problem symptoms table.

6 CIRCUIT INSPECTION OR PARTS INSPECTION

(a) Confirm the circuit in the system or the part that should be checked using the problem symptoms table or the results obtained in step 4.

7 REPAIR

(a) Repair the affected system or part according to the instructions in step 6.

8 CONFIRMATION TEST

(a) 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 the first time.

General information

A large number of ECU controlled systems are used in the HIGHLANDER. In general, ECU controlled systems are considered to be very intricate, requiring a high level of technical knowledge to troub ...

Customer problem analysis

HINT: In troubleshooting, the problem symptoms must be confirmed accurately. Preconceptions should be discarded in order to give an accurate judgement. To clearly understand what the probl ...

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