Toyota Corolla 2004 Repair Manual - HOW TO PROCEED WITH TROUBLESHOOTING
01–20
–INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
01035–10
HOW TO PROCEED WITH TROUBLESHOOTING
HINT:
Carry out troubleshooting in accordance with the procedures on the following page. Here, only the basic
procedures are shown. Details are provided in the Diagnostics Section, showing the most effective methods
for each circuit. Confirm the troubleshooting procedures first for the relevant circuit before beginning troubleshooting of that circuit.
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
(a) Check the battery positive voltage.
Voltage: 11 – 14 V (Engine stopped)
(b) Visually check the wire harness, connectors and fuses for open and short, etc.
(c) Warm up the engine to the normal operating temperature.
(d) Confirm the problem symptoms and conditions, and check for DTCs according to the related chart.
OK Go to step 5
NG
4 DTC chart
(a) Check the results obtained in step 3, then confirm the inspection procedures for the system or the part
which should be checked using the DTC chart.
Go to step 6
5 Problem symptoms chart
(a) Check the results obtained in step 3, then confirm the inspection procedures for the system or the part
which should be checked using the problem symptoms table.
6 Circuit inspection or parts inspection
(a) Confirm the circuit for the system or the part which should be checked using the problem symptoms
table or the results obtained in step 4.
7 Repair
(a) Repair the affected system or part in accordance with the instructions in step 6.
2004 COROLLA (RM1037U)
23Author: Date:
–INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
01–21
8 Confirmation test
(a) After completing repairs, confirm that the problem has been solved (If the problem does not recur, per-
form a confirmation test under the same conditions and in the same environment as when it occurred
for the first time).
END
2004 COROLLA (RM1037U)
24Author: Date:
01–22
–INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
CUSTOMER PROBLEM ANALYSIS
HINT:
In troubleshooting, the problem symptoms must be confirmed accurately, meaning that all preconcep-
tions must be set aside in order to make an accurate judgement. To ascertain what the problem symptoms are, it is extremely important to ask the customer about the problem and conditions when it occurred.
The following 5 items are important points in the problem analysis. Past problems which are thought
to be unrelated and the repair history, etc. may also help in some cases. Therefore, as much information as possible should be gathered and its relationship with the problem symptoms should be correctly
ascertained for use as reference in troubleshooting. A customer problem analysis table is provided for
your use in the Diagnostics Section for each system.
Important Points with Customer Problem Analysis
What ––––– Vehicle model, system name
When ––––– Date, time, occurrence frequency
Where ––––– Road conditions
Under what conditions? ––––– Running conditions, driving conditions, weather conditions
How did it happen? ––––– Problem symptoms
(Sample) Supplemental restraint system check sheet.
CUSTOMER PROBLEM ANALYSIS CHECK
Supplemental Restraint System Check Sheet
Customer’s Name
Date Vehicle Brought In
Date Problem First Occurred
Weather
Temperature
Vehicle Operation
/ /
Fine Cloudy
Approx.
Starting Idling
Driving Constant speed Acceleration
Inspector’s
Name
Production Date
Odometer Reading
Other
VIN
Licence No.
Rainy Snowy
/ /
/ /
Other
Deceleration[
km
miles
]
2004 COROLLA (RM1037U)
25Author: Date:
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