Symptom Confirmation & Diagnostic Trouble Code
NOTE:
- The diagnostic system in HIGHLANDER has various functions. The first function is the Diagnostic Trouble Code (DTC) Check in which a malfunction in the signal circuits to the ECU is stored in code form in the ECU memory. Another function is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly. By using these check functions, possible areas of the problem can be narrowed down quickly and troubleshooting can be performed effectively. The diagnostic functions are incorporated in the following systems in HIGHLANDER.
- In the DTC check, it is very important to determine whether the problem indicated by the DTC is still occurring or has occurred in the past but returned to normal at present. In addition, it must be checked in the problem symptom check whether the malfunction indicated by the DTC is directly related to the problem symptom or not. For this reason, the DTC should be checked before and after the symptom confirmation to determine the current conditions. If this is not done, it may, depending on the case, result in an unnecessary troubleshooting for normally operating systems, making it more difficult to detect the problem area, or trying to repair irrelevant areas. Therefore always follow the procedures in the correct order and perform the DTC check.
- A flow chart showing how to proceed with the troubleshooting using the diagnostic trouble code (DTC) check is shown here at step 1. This flow chart shows how to utilize the DTC check effectively. Then, by carefully checking the results, this chart indicates how to proceed either to the DTC troubleshooting or to the troubleshooting of the problem symptoms table.
- DTC CHECK
- MAKING A NOTE AND CLEARING OF DTC DISPLAYED
- SYMPTOM CONFIRMATION SYMPTOM CONFIRMATION
A Problem Symptoms Exist B No Problem Symptoms Exist - a : Go to step 5 .
- b : Go To Next Step
- SIMULATION TEST USING
- DTC CHECK DTC CHECK
A DTC Displayed B Normal Code Displayed - A : TROUBLESHOOTING OF PROBLEM INDICATED BY DTC
- B : Go To Next Step
- SYMPTOM CONFIRMATION SYMPTOM CONFIRMATION
A No Problem Symptoms Exist B Problem Symptoms Exist If a DTC is displayed in the initial DTC check, it indicates that a trouble may have occurred in a wire harness or connector in that circuit in the past, therefore check the wire harness and connectors (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
- A : SYSTEM NORMAL
- B : TROUBLESHOOTING OF EACH PROBLEM SYMPTOM
The problem is still occurring in a place other than the diagnostic circuit (The DTC displayed first is either for a past problem or it is a secondary problem).