IN-30
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INTRODUCTION
HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
30
Author:
Date:
2005 LEXUS IS300 (RM1140U)
5.
PROBLEM SYMPTOMS TABLE
The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to
troubleshoot when, during a DTC check, a ”Normal” code is displayed in the diagnostic trouble code check
but the problem is still occurring. Numbers in the table show the inspection order in which the circuits or parts
should be checked.
HINT:
In some cases, a problem is not detected by the diagnostic system even though a problem symptom is pres-
ent. It is possible that the problem is occurring outside the detection range of the diagnostic system, or that
the problem is occurring in a completely different system.
Symptom
Suspect Area
See page
Engine does not crank (Does not start)
No initial combustion (Does not start)
No complete combustion (Does not start)
1. Starter and starter relay
1. ECM power source circuit
2. Fuel pump control circuit
3. Engine control module (ECM)
1. Starter signal circuit
2. Fuel pump control circuit
1. Fuel pump control circuit
DI-147
DI-151
IN-29
PROBLEM SYMPTOMS TABLE
1. Compression
2. Fuel pump control circuit
1. A/C signal circuit
2. Fuel pump control circuit
1. A/C signal circuit (Compressor circuit)
2. ECM power source circuit
1. Starter signal circuit
2. Fuel pump control circuit
1. Starter signal circuit
2. Fuel pump control circuit
3. Compression
idling)
High engine idle speed (Poor idling)
Hot engine
Cold engine (Difficult to start)
Engine cranks normally (Difficult to start)
AC-88
DI-144
DI-151
EM-3
DI-151
Problem Symptom
Page
Indicates the page where the flow chart for each circuit
is located.
Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for a problem
symptom.
Circuit or Part Name
Indicates the circuit or part which needs to be checked.
ST-2
ST-17
DI-144
DI-151
DI-144
DI-151
