Symptom Confirmation And Diagnostic Trouble Code; Making A Note And Clear The Dtcs; Simulation Test Using The Symptom Simulation Methods; How To Troubleshoot Ecu Controlled Systems - Toyota Corolla 2004 Manual

SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE

HINT:
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The diagnostic system in COROLLA 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, it is possible to quickly narrow
down potential problem areas and troubleshooting can be performed effectively. The diagnostic func-
tions are incorporated in the following systems in the COROLLA.

SFI System

ABS with EBD System

Electronic Controlled Automatic Transaxle [ECT]

Supplemental Restraint System

Cruise Control System
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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 during the problem
symptom check, it a check must be made on 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
symptom confirmation to determine the current conditions. If this is not done, it may, depending on the
case, result in unnecessary troubleshooting for systems that are operating normally. This would make
more difficult to detect the problem area or to try to repair irrelevant areas. Therefore, always follow
the procedures in the correct order and perform the DTC check.
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A flow chart showing how to proceed with troubleshooting using the diagnostic trouble code (DTC)
check is shown the this page. 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.
1 DTC check
2

Making a note and clear the DTCs

3 Symptom confirmation
b
4

Simulation test using the symptom simulation methods

2004 COROLLA (RM1037U)
INTRODUCTION
System
– HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
Diagnostic Trouble
Code Check
(with Check Mode)
(with Check Mode)
a Go to step 5
Author :
Input Signal Check Diagnostic Test
(Sensor Check) Mode (Active Test)
Problem symptoms exist
No problem symptoms exist
Date :
01–23
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