service MITSUBISHI 380 2005 Workshop Manual

TROUBLESHOOTING GUIDELINES
GENERAL00-6
TROUBLESHOOTING GUIDELINESM1001008800340
VERIFY THE COMPLAINT
Make sure the customer's complaint and the ser-
vice writer's work order description are under-
stood before starting work.
Make sure you understand the correct operation
of the system. Read the service manual descrip-
tion to verify normal system operation.
Operate the system to see the symptoms. Look
for other symptoms that were not reported by the
customer, or on the work order, that may be
related to the problem.
DETERMINE POSSIBLE CAUSES
Compare the confirmed symptoms to the diagnostic
symptom indexes to find the right diagnosis proce-
dure.
If the confirmed symptoms cannot be found on any
symptom index, determine other possible causes.
Analyze the system diagrams and list all possible
causes for the problem symptoms.
Rank all these possible causes in order of proba-
bility, based on how much of the system they
cover, how likely they are to be the cause, and
how easy they will be to check. Be sure to take
experience into account. Consider the causes of
similar problems seen in the past. The list of
causes should be ranked in order from general to
specific, from most-likely to least-likely, and from
easy-to-check to hard-to-check.
FIND THE PROBLEM
After the symptoms have been confirmed, and prob-
able causes have been identified, the next step is to
make step-by-step checks of the suspected system
components, junctions, and links in logical order.
Use the diagnostic procedures in the service manual
whenever possible. Follow these procedures care-
fully to avoid missing an important step in the diagno-
sis sequence. It might be the skipped step that leads
to the solution of the problem.
If the service manual doesn't have step-by-step pro-
cedures to help diagnose the problem, make a series
of checks based on the ranked list of probable
causes. Troubleshooting checks should be made in
the order that the list of causes was ranked:
general to specific
most-likely to least-likely
easy-to-check to hard-to-check
REPAIR THE PROBLEM
When the step-by-step troubleshooting checks find a
fault, perform the proper repairs. Make sure to fix the
root cause of the problem, not just the symptom. Just
fixing the symptom, without fixing the root cause, will
cause the symptom to eventually return.
VERIFY THE REPAIR
After repairs are made, recheck the operation of the
system to confirm that the problem is eliminated. Be
sure to check the system thoroughly. Sometimes
new problems are revealed after repairs have been
made.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-7
HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE
POINTS
TROUBLESHOOTING CONTENTSM1001013300062
During diagnosis, a DTC code associated with
other system may be set when the ignition
switch is turned on with connector(s) discon-
nected. On completion, confirm all systems
for DTC code(s). If DTC code(s) are set, erase
them all.
When the DIAGNOSTIC TOOL (MUT-III)
detects a diagnostic trouble code, its display
informs users whether a mechanical problem
currently exists (“current trouble”) or whether
it existed before but normal operation has
been restored (“past trouble”). However, if an
MPI, TPMS or SRS airbag-related DTC is set,
“Active DTC/Stored DTC” is not displayed. In
this case, follow the diagnosis procedure for
current trouble.
If a trouble, detected in a CAN communica-
tion-capable system, can be reproduced,
diagnose the CAN bus lines (Refer to GROUP
54C, Can Bus Line Diagnostics Chart
P.54C-15 or P.54C-15).
Troubleshooting of electronic control systems for
which the MUT -III can be used follows the basic out-
line described below. Even in systems for which the
MUT-III cannot be used, part of these systems still
follow this outline.
1. STANDARD FLOW OF DIAGNOSTIC
TROUBLESHOOTING
Troubleshooting strategy is shown in each group.
2. SYSTEM OPERATION AND SYMPTOM
VERIFICATION TESTS
If verification of the symptom(s) is difficult, proce-
dures for checking operation and verifying symptoms
are shown.
3. DIAGNOSTIC FUNCTION
The following trouble code diagnoses are shown.
How to read diagnostic trouble codes
How to erase diagnostic trouble codes
Input inspection service points
4. DIAGNOSTIC TROUBLE CODE CHART
If the MUT-III displays a diagnostic trouble code, find
the applicable inspection procedure according to this
chart.
5. SYMPTOM CHART
If there are symptoms, even though the MUT-III
shows that no DTCs are set, inspection procedures
for each symptom will be found by using this chart.
6. DIAGNOSTIC TROUBLE CODE
PROCEDURES
Indicates the inspection procedures corresponding to
each diagnostic trouble code. (Refer to P.00-9).
7. SYMPTOM PROCEDURES
Indicates the inspection procedures corresponding to
each symptom listed in the Symptom Chart (Refer to
P.00-9).
8. SERVICE DATA REFERENCE TABLE
Inspection items and normal judgment values have
been provided in this chart as reference information.
9. CHECK AT ECU TERMINALS
Terminal numbers for the ECU connectors, inspec-
tion items, and standard values have been provided
in this chart as reference information.
.
TERMINAL VOLTAGE CHECKS
1. Use correct tool to check each pin location on the
ENGINE-ECU Check harnes MB992044 and
measure with voltmeter.
Short-circuiting the positive (+) test probe
between a connector terminal and ground could
damage the vehicle wiring, the sensor, the ECU,
or all three. Use care to prevent this!
2. Insert the correct terminal tool into each of the
ENGINE-ECU check harness connector
terminals, and measure the voltage while referring
to the check chart.
NOTE: Measure voltage with the ECU connectors
connected.
You may find it convenient to pull out the ECU to
make it easier to connect the ENGINE-ECU check
harness.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-8
Checks don't have to be carried out in the order
given in the chart.
3. If voltage readings differ from normal condition
values, check related sensors, actuators, and
wiring. Replace or repair as needed.
4. After repair or replacement, recheck with the
voltmeter to confirm that the repair has corrected
the problem.
.
TERMINAL RESISTANCE AND
CONTINUITY CHECKS
1. Turn the ignition switch to the “LOCK” (OFF)
position.
2. Disconnect the ECU connector.
If resistance and continuity checks are per-
formed on the wrong terminals, damage to the
vehicle wiring, sensors, ECU, and/or ohmmeter
may occur. Use care to prevent this!
3. Measure the resistance and check for continuity
between the terminals of the ENGIN-ECU check
harness MB992044 connector while referring to
the check chart.
NOTE: Checks don't have to be carried out in the
order given in the chart.
4. If the ohmmeter shows any deviation from the
Normal Condition value, check the corresponding
sensor, actuator and related electrical wiring, then
repair or replace.
5. After repair or replacement, recheck with the
ohmmeter to confirm that the repair has corrected
the problem.
10. INSPECTION PROCEDURES USING
AN OSCILLOSCOPE
When there are inspection procedures using an
oscilloscope, these are listed.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-9
HOW TO USE THE INSPECTION PROCEDURESM1001013500066
The causes of many of the problems occurring in electric circuitry are generally the connectors, components,
the ECU, and the harnesses between connectors, in that order. These inspection procedures follow this
order. They first try to discover a problem with a connector or a defective component.
DTC P0202: Injector Circuit Malfunction - Cylinder 2.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-10
CURRENT TROUBLE
Indicates that the trouble is currently present. Carry
out troubleshooting as described in the applicable
inspection procedure.
PAST TROUBLE
Indicates that the trouble is historic, but normal oper-
ation has been restored. Observe the applicable
inspection procedure with particular emphasis on
connector(s) and wiring harness.
HARNESS INSPECTION
Check for an open or short circuit in the harness
between the terminals which were faulty according to
the connector measurements. Carry out this inspec-
tion while referring to GROUP 00E, Harness Con-
nector Inspection P.00E-2. Here, “Check harness
between power supply and terminal xx” also includes
checking for blown fuse. For inspection service
points when there is a blown fuse, refer to "Inspec-
tion Service Points for a Blown Fuse P.00-16."

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-11
MEASURES TO TAKE AFTER
REPLACING THE ECU
If the trouble symptoms have not disappeared even
after replacing the ECU, repeat the inspection proce-
dure from the beginning.
CONNECTOR MEASUREMENT SERVICE POINTSM1001013600063
Turn the ignition switch to the "LOCK" (OFF) position when
connecting and disconnecting the connectors. Turn the ignition
switch to "ON" when measuring, unless there are instructions
to the contrary.
IF INSPECTING WITH THE CONNECTOR
CONNECTED
Be sure to use special tool. Never insert a test probe from the
harness side, as this will reduce the waterproof performance
and result in corrosion.
IF INSPECTING WITH THE CONNECTOR
CONNECTED CONNECTORS>
Check by inserting the multi-meter test probe from the harness
side. Note that if the connector (control unit, etc.) is too small to
permit insertion of the test probe, it should not be forced; use
the test probe tool for this purpose.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-12
IF INSPECTING WITH THE CONNECTOR
DISCONNECTED FEMALE PIN>
Required Special Tool:
MB991219: Inspection Harness (Included in MB991223,
Harness Set)
The special tool MB991219 for connector pin contact pres-
sure should be used. The test probe should never be forc-
ibly inserted, as it may cause a defective contact.
From back side of the connector (SRS-ECU harness side
connector)
Since the SRS-ECU harness connector is plated to improve
conductivity, observe the warning below when checking this
connector.
Insert the test probe tool into the connector from the
harness side, and connect the tester to the test probe
tool. If any tool other than the test probe tool is used,
it may cause damage to the harness and other com-
ponents. Furthermore, measurement should not be
carried out by touching the test probe tool directly
against the terminals from the front of the connector.
The terminals are plated to increase their conductiv-
ity, so that if they are touched directly by the test
probe tool, the plating may break, which will decrease
reliability.
IF INSPECTING WITH THE CONNECTOR
DISCONNECTED PIN>
At this time, be careful not to short the connector pins with
the test probes. Doing so may damage the circuits inside
the ECU.
Touch the pin directly with the test probe.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-13
CONNECTOR INSPECTION SERVICE POINTSM1001013700060
VISUAL INSPECTION
Connector is disconnected or improperly connected
Connector pins are pulled out
Stretched an broken wires at terminal section
Low contact pressure between male and female terminals
Low connection pressure due to rusted terminals or foreign
matter lodged in terminals
.
CONNECTOR PIN INSPECTION
If the connector pin stopper is damaged, the terminal connec-
tions (male and female pins) will not be perfect even when the
connector body is connected, because the pins may pull out of
the back side of the connector. Therefore, gently pull the wires
one by one to make sure that no pins pull out of the connector.
.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-14
CONNECTOR ENGAGEMENT INSPECTION
Required Special Tool:
MB991219: Inspection Harness (contained in MB991223
Test Harness)
Use special tool MB991219 to inspect the engagement of the
male pins and female pins. [Pin drawing force: 1 N (0.2 pound)
or more]
HOW TO COPE WITH INTERMITTENT
MALFUNCTIONS
M1001013900064
Most intermittent malfunctions occur under certain conditions. If
those conditions can be identified, the cause will be easier to
find.
.
TO COPE WITH INTERMITTENT MALFUNCTION;
1. ASK THE CUSTOMER ABOUT THE
MALFUNCTION
Ask what it feels like, what it sounds like, etc. Then ask about
driving conditions, weather, frequency of occurrence, and so
on.
.
2. DETERMINE THE CONDITIONS FROM THE
CUSTOMER'S RESPONSES
Typically, almost all intermittent malfunctions occur from condi-
tions like vibration, temperature and/or moisture change, poor
connections. From the customer's responses, it should be rea-
soned which condition is most likely.
.
3. USE SIMULATION TEST
Use the simulation tests below to attempt to duplicate the cus-
tomer's complaint. Determine the most likely circuit(s) and per-
form the simulation tests on the connectors and parts of that
circuit(s). Be sure to use the inspection procedures provided for
diagnostic trouble codes and trouble symptoms.
For temperature and/or moisture condition related intermittent
malfunctions, try to change the conditions of the suspected cir-
cuit components, then use the simulation tests below.
.

HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE POINTS
GENERAL00-15
4. VERIFY THE INTERMITTENT MALFUNCTION IS
ELIMINATED
Repair the malfunctioning part and try to duplicate the condi-
tion(s) again to verify the intermittent malfunction has been
eliminated.
.
SIMULATION TESTS
NOTE: In case of difficulty in finding the cause of the intermit-
tent malfunction, the data recorder function in the
DIAGNOSTIC TOOL (MUT-III) is effective.
For these simulation tests, shake, then gently bend, pull, and
twist the wiring of each of these examples to duplicate the inter-
mittent malfunction.
Shake the connector up-and-down, and right-and-left.
Shake the wiring harness up-and-down, and right-and-left.
Especially, check the splice points of wiring harnesses care-
fully. Refer to GROUP 00E, Harness Connector Inspection
P.00E-2.
Shake the part or sensor.