Toyota FJ Cruiser (GSJ 10, 15 series). Instruction — part 271
INTRODUCTION – HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
IN–39
IN
HINT:
•
In troubleshooting, confirm that the problem symptoms
have been accurately identified. Preconceptions should be
discarded in order to make an accurate judgment. To
clearly understand what the problem symptoms are, it is
extremely important to ask the customer about the
problem and the conditions at the time the malfunction
occurred.
•
Gather as much information as possible for reference.
Past problems that seem unrelated may also help in some
cases.
•
The following 5 items are important points in the problem
analysis:
3.
SYMPTOM CONFIRMATION AND DIAGNOSTIC
TROUBLE CODE
HINT:
The diagnostic system in the FJ CRUISER has various
functions.
•
The first function is the Diagnostic Trouble Code
(DTC) check. A DTC is a code stored in the ECU
memory whenever a malfunction in the signal circuits
to the ECU occurs. In a DTC check, a previous
malfunction's DTC can be checked by a technician
during troubleshooting.
•
Another function is the Input Signal Check, which
checks if the signals from various switches are sent to
the ECU correctly.
By using these functions, the problem areas can be
narrowed down and troubleshooting is more effective.
Diagnostic functions are incorporated in the following
system in the FJ CRUISER.
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
System
DTC Check
(Normal Mode)
DTC Check
(Check Mode)
Freeze-frame
Data
Sensor Check
/ Test Mode
(Input Signal
Check)
Data List
Active Test
Customize
Parameter
1GR-FE SFI
SYSTEM
{
{
{
-
{
{
-
A750E
AUTOMATIC
TRANSAXLE
SYSTEM
{
{
-
-
{
{
-
A750F
AUTOMATIC
TRANSAXLE
SYSTEM
{
{
-
-
{
{
-
VEHICLE
STABILITY
CONTROL
SYSTEM
{
-
{
{
{
{
-
AIRBAG
SYSTEM
{
{
-
-
{
-
-
IN–40
INTRODUCTION – HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
IN
•
In the DTC check, it is very important to determine
whether the problem indicated by the DTC is either: 1)
still occurring, or 2) occurred in the past but has since
returned to normal. In addition, the DTC should be
compared to the problem symptom to see if they are
related. For this reason, DTCs should be checked
before and after confirmation of symptoms (i.e.,
whether or not problem symptoms exist) to determine
current system conditions, as shown in the flowchart
below.
•
Never skip the DTC check. Failing to check DTCs
may, depending on the case, result in unnecessary
troubleshooting for systems operating normally or
lead to repairs not related to the problem. Follow the
procedures listed in the flowchart in the correct order.
•
The following flowchart shows how to proceed with
troubleshooting using the DTC check. Directions from
the flowchart will indicate how to proceed either to
DTC troubleshooting or to the troubleshooting of each
problem symptom.
NEXT
NEXT
Result
OCCUPANT
CLASSIFICATI
ON SYSTEM
{
-
-
-
{
-
-
CRUISE
CONTROL
SYSTEM
{
-
-
-
{
-
-
MULTIPLEX
COMMUNICAT
ION
{
-
-
-
-
-
-
CAN
COMMUNICAT
ION SYSTEM
{
-
-
-
-
-
-
System
DTC Check
(Normal Mode)
DTC Check
(Check Mode)
Freeze-frame
Data
Sensor Check
/ Test Mode
(Input Signal
Check)
Data List
Active Test
Customize
Parameter
1
DTC CHECK
2
MAKE A NOTE OF DTCS DISPLAYED AND THEN CLEAR MEMORY
3
SYMPTOM CONFIRMATION
Result
Proceed to
No symptoms exist
A
Symptoms exist
B
INTRODUCTION – HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
IN–41
IN
B
A
NEXT
Result
B
A
Result
If a DTC was displayed in the initial DTC check, the problem
may have occurred in a wire harness or connector in that
circuit in the past. Check the wire harness and connectors.
B
A
The problem is still occurring in a place other than the
diagnostic circuit (the DTC displayed first is either for a past
problem or a secondary problem).
4.
SYMPTOM SIMULATION
HINT:
The most difficult case in troubleshooting is when no
problem symptoms occur. In such a case, a thorough
problem analysis must be carried out. A simulation of the
same or similar conditions and environment in which the
problem occurred in the customer's vehicle should be
carried out. No matter how much skill or experience a
technician has, troubleshooting without confirming the
problem symptoms will lead to important repairs being
overlooked and mistakes or delays.
Go to step 5
4
SIMULATION TEST USING SYMPTOM SIMULATION METHODS
5
DTC CHECK
Result
Proceed to
DTC is not output
A
DTC is output
B
TROUBLESHOOTING OF PROBLEM
INDICATED BY DTC
6
SYMPTOM CONFIRMATION
Result
Proceed to
Symptoms exist
A
No symptoms exist
B
SYSTEM NORMAL
TROUBLESHOOTING OF EACH PROBLEM SYMPTOM
IN–42
INTRODUCTION – HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
IN
For example:
With a problem that only occurs when the engine is
cold or as a result of vibration caused by the road
during driving, the problem can never be
determined if the symptoms are being checked on
a stationary vehicle or on a vehicle with a warmed-
up engine. Vibration, heat or water penetration
(moisture) is difficult to reproduce. The symptom
simulation tests below are effective substitutes for
the conditions and can be applied on a stationary
vehicle. Important points in the symptom
simulation test:
In the symptom simulation test, the problem
symptoms as well as the problem area or parts
must be confirmed. First, narrow down the
possible problem circuits according to the
symptoms. Then, connect the tester and carry out
the symptom simulation test, judging whether the
circuit being tested is defective or normal. Also,
confirm the problem symptoms at the same time.
Refer to the problem symptoms table for each
system to narrow down the possible causes.
(a) VIBRATION METHOD:
When a malfunction seems to occur as a result of
vibration.
(1) PART AND SENSOR
Apply slight vibration with a finger to the part of
the sensor suspected to be the cause of the
problem, and check whether or not the
malfunction occurs.
NOTICE:
Applying strong vibration to relays may open
them.
(2) CONNECTORS
Slightly shake the connector vertically and
horizontally.
(3) WIRE HARNESS
Slightly shake the wire harness vertically and
horizontally.
HINT:
The connector joint and fulcrum of the vibration
are the major areas that should be checked
thoroughly.
(b) HEAT METHOD:
When a malfunction seems to occur when the area
in question is heated.
(1) Heat the component that is the possible cause of
the malfunction with a hair dryer or similar
device. Check if the malfunction occurs.
NOTICE:
•
Do not heat to more than 60
°C (140°F).
Exceeding this temperature may damage
components.
Vibrate Slightly
Vibrate Slightly
Shake Slightly
B071602E03
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