1997 MITSUBISHI TRITON Workshop Manual

GENERAL ± How to Use Troubleshooting/Inspection Service Points00-6
HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE
POINTS
00100020091
Troubleshooting of electronic control systems for which the MUT-II can be used follows the basic outline
described below. Furthermore, even in systems for which the MUT-II cannot be used, part of these systems
still follow this outline.
TROUBLESHOOTING CONTENTS
1. STANDARD FLOW OF DIAGNOSIS TROUBLESHOOTING
The troubleshooting sections follow the basic diagnosis flow which is given below. If the diagnosis
flow is different from that given below, or if additional explanation is required, the details of such
differences or additions will also be listed.
Diagnosis method
Gathering information
from the customer.
Check trouble symptom.
Reoccurs Does not reoccur.
Read the diagnosis code
No diagnosis code
or communication
with MUT-II not
possible
Refer to the INSPECTION
CHART FOR TROUBLE
SYMPTOMS (Refer to
applicable group.)Diagnosis code
displayed.
Read the diagnosis code
Diagnosis code
displayed.No diagnosis
code
After taking note of the
malfunction code, erase
the diagnosis code
memory
Recheck trouble symptom.
Diagnosis code
displayed.
Read the diagnosis codes.
No diagnosis
code
Refer to the INSPECTION CHART FOR DIAGNOSIS
CODES (Refer to applicable group.)INTERMITTENT MALFUNCTIONS (Refer to P.00-12.)
2. SYSTEM OPERATION AND SYMPTOM VERIFICATION TESTS
If verification of the trouble symptoms is difficult, procedures for checking operation and verifying
trouble symptoms are shown.
3. DIAGNOSIS FUNCTION
Details which are different from those in the ªDiagnosis Functionº section on the next page are listed.

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GENERAL ± How to Use Troubleshooting/Inspection Service Points00-9
HOW TO USE THE INSPECTION PROCEDURES
The causes of a high frequency of problems occurring in electronic circuitry are generally the connectors,
components, the ECU and the harnesses between connectors, in that order. These inspection procedures
follow this order, and they first try to discover a problem with a connector or a defective component.

Indicator does not turn on or off even if control
mode switch is pressed.

Indicator switch should not be illuminated is
illuminated.Probable cause
OK
OK
OK
Measure at switch connector A-44

Disconnect the connector, and measure at the harness
side.

Voltage between terminal 6 ± earth and terminal 8 ±
earth
OK:Approx. 5V
OK
NG
Check the following connector. A-44
Repair
OK
Check trouble symptom.
Replace the ECS-ECU.
In the above cases, the ECS switch circuit is defective or the indicator
circuit is defective.
CHECKING PROCEDURE 4
2. Indicates inspection carried out using the
MUT-II.
Indicates the operation and inspection proce-
dures.
Indicates the OK judgement conditions.
3. Detailed inspection procedures (methods)
such as component inspection and circuit
inspection are listed on a separate page, and
are given here for reference.
5. Inspect the contact condition at each connector terminal.
(Refer to Connector Inspection Service Points.)
The connector position can be located in the wiring diagram in the
electrical wiring manual by means of this symbol.
Caution
After carrying out connector inspection, always be sure to
reconnect the connector as it was before.
6. Confirm that there are trouble symptoms. If trouble symptoms have
disappeared, the connector may have been inserted incorrectly and the
trouble symptom may have disappeared during inspection.
If it seems that trouble symptoms still remain, proceed to the next page of
instructions.
7. If trouble symptoms still remain up to this stage, there is a possibility that there is an
open or short circuit in the harness between the connectors, so check the harness.
Alternatively, the cause may be a defective ECU, so try replacing the ECU and check
if the trouble symptom disappears.
NGECU switch component inspection (Refer to P.3-44.)
NG
1. Comments on the diagnosis code or trouble
symptom above.
MUT-II Data list
17 Control mode selection switch
OK:Voltage changes between approx. 0V
approx.
2.5V
approx. 5V when the switch is operated.
4. Indicates voltage and resistance to be measured at a particular
connector.
(Refer to Connector Measurement Service Points.)
The connector position can be located in the wiring diagram in the
electrical wiring manual by means of this symbol.
Indicates operation and inspection procedures, inspection terminals
and inspection conditions.
Indicates the OK judgement conditions.
HARNESS INSPECTION
Check for an open or short circuit in the harness between the terminals which were defective according
to the connector measurements. Carry out this inspection while referring to the electrical wiring manual.
Here, ªCheck harness between power supply and terminal xxº also includes checking for blown fuses.
For inspection service points when there is a blown fuse, refer to ªInspection Service Points for a Blown
Fuse.º
MEASURES TO TAKE AFTER REPLACING THE ECU
If the trouble symptoms have not disappeared even after replacing the ECU, repeat the inspection procedure
from the beginning.

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