IN-24
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INTRODUCTION
HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
24
Author:
Date:
2005 LEXUS IS300 (RM1140U)
2.
SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the LEXUS IS300 fulfills various functions.
The first function is the Diagnostic Trouble Code (DTC) Check. In a DTC Check,a previous malfunc-
tion’s DTC can be checked by a technician during troubleshooting. (A DTC is a code stored in the ECU
memory whenever a malfunction in the signal circuits to the ECU occurs.)
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, the problem areas can be narrowed down and
troubleshooting is more effective. Diagnostic functions are incorporated in the following systems in the
LEXUS IS300.
System
Diagnostic Trouble
Code Check
Input Signal Check
(Sensor Check)
Diagnostic Test
Mode (Active Test)
Engine
(with Check Mode)
Automatic Transmission
(with Check Mode)
ABS with EBD & BA & TRAC System
ABS with EBD & BA & TRAC & VSC System
Supplemental Restraint System
Theft Deterent System
Cruise Control System
Engine Immobiliser System
Combination Meter System
Body Control System
Multiplex Communication System
LEXUS Navigation System
Air Conditioning System
