TROUBLESHOOTING
- How to Carry Out Troubleshootin
g
PRE-DIAGNOSTIC QUESTIONIN
G
Refering to the Pre-diagnostic Questioning
Checksheet, ask the customer about the
problem in as much detail as possible
.
CHECKING AND CLEARING DIAGNOSTIC
CODES (PRECHECK
)
Before confirming the symptoms, check the
diagnostic code in the normal mode and
make a note of any malfunction codes dis-
played, then clear the codes
.
3
SETTING DIAGNOSTIC TEST MOD
E
(for vehicles equipped with diagnostic test
mode
.
)
In order to find the cause of the problem
more quickly, set the system in the
diagnostic test mode
.
SYMPTOM CONFIRMATIO
N
Confirm the symptoms of the problem
.
SYMPTOM SIMULATIO
N
If the symptoms do not reappear, use the
symptom simulation method to reproduce
them
.
CHECKING DIAGNOSTIC COD
E
Check the
diagnostic codes
. If the normal
code is output, proceed to step
❑
~
. If a mal-
function code is output, proceed to ste
p
BASIC INSPECTION
8
Carry out
a basic inspection, such as an ig-
nition spark
check,
fuel pressure
check, etc
.
8
DIAGNOSTIC CODE
S
If a malfunction code was output in step
6
check the trouble area indicated by the
diagnostic code chart
.
1 1
1
2
1
3
15
SYMPTOM CHAR
T
If a trouble was not confirmed in step
❑
perform troubleshooting according to the in-
spection items in the symptom chart
.
CIRCUIT INSPECTIO
N
Proceed with the diagnosis of each circuit
between the ECU and the component in
accordance with the inspection items
confirmed in step ® or step
❑
. Determine
whether the cause of the trouble is in the
sensors, the actuators, the wire harness or
connector, or the ECU
.
INSPECTION OF COMPONENTS
Inspect the problematic components
.
SYMPTOM SIMULATIO
N
If the cause of the trouble is momentary
(intermittent) interruptions or shorts, pull
gently on the wire harness, connectors, and
terminals, and shake them gently to isolate
the place where the trouble is occurring due
to poor contact
.
ADJUSTMENT
AND/OR REPAI
R
After the cause of the trouble is located, per-
form the necessary adjustment or repair
.
CLEARING DIAGNOSTIC CODES
Clear the diagnostic codes
.
CONFIRMATION TES
T
After completing the adjustment or repairs,
check to see whether the trouble has been
eliminated, and perform a test drive to make
sure the entire engine control system is
operating normally and that the diagnostic
code displayed is the normal code
.
151
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