display MITSUBISHI TRITON 1997 User Guide

MPI ± Troubleshooting13A-35
INSPECTION PROCEDURE 15
Hesitation, sag or stumble
Probable cause
In cases such as the above, the cause is probably that ignition system, air/fuel mixture
or compression pressure is defective.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the fuel supply system

Malfunction of the EGR control solenoid valve system

Poor compression
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.
(Refer to P.13A-51, INSPECTION PROCEDURE 40.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)

Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)

Check the fuel filter or fuel line for clogging.
INSPECTION PROCEDURE 16
The feeling of impact or vibration when accelerating
Probable cause
In cases such as the above, the cause is probably that there is an ignition leak
accompanying the increase in the spark plug demand voltage during acceleration.
Malfunction of the ignition system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the following items.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check for occurrence of ignition leak.

MPI ± Troubleshooting13A-36
INSPECTION PROCEDURE 17
The feeling of impact or vibration when decelerating.
Probable cause
Malfunction of the ISC system is suspected.
Malfunction of the ISC system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the ISC servo for operation sound. (Refer to P.13A-90.)NGCheck the ISC servo system.
(Refer to P.13A-45, INSPECTION PROCEDURE 31.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
Clean the throttle valve area. (Refer to P.13A-78.)
INSPECTION PROCEDURE 18
Poor acceleration
Probable cause
Defective ignition system, abnormal air-fuel ratio, poor compression pressure, etc.
are suspected.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the fuel supply system

Poor compression pressure

Clogged exhaust system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.
(Refer to P.13A-51, INSPECTION PROCEDURE 40.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)

Check the fuel filter or fuel line for clogging.

Broken air intake hose

Clogged air cleaner

MPI ± Troubleshooting13A-37
INSPECTION PROCEDURE 19
Surge
Probable cause
Defective ignition system, abnormal air-fuel ratio, etc. are suspected.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the EGR control solenoid valve system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if surge occurs.
(Refer to P.13-52, INSPECTION PROCEDURE 41.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)
INSPECTION PROCEDURE 20
Knocking
Probable cause
In cases as the above, the cause is probably that the heat value of the spark plug
is inappropriate.
Inappropriate heat value of the spark plug
Check the following items.

Spark plugs

Check if foreign materials (water, alcohol, etc.) got into fuel.
INSPECTION PROCEDURE 21
Dieseling
Probable cause
Fuel leakage from injectors is suspected.
Fuel leakage from injectors
Check the injectors for fuel leakage.

MPI ± Troubleshooting13A-38
INSPECTION PROCEDURE 22
Too high CO and HC concentration when idling
Probable cause
Abnormal air-fuel ratio is suspected.
Malfunction of the air-fuel ratio control system

Deteriorated catalyst
Check trouble symptom.
No
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II Data list
21 Engine coolant temperature sensor. (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air temperature sensor system. (Refer to P.13A-12,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600 ± 1,000 mV when racing suddenly (Refer to P.13A-57.)NGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Repeat 0 ± 400 mV and 600 ± 1,000 mV alternately when
idling. (Refer to P.13A-57.)OK
NG
Check the fuel pressure. (Refer to P.13A-81.)
OK
NG
Check the following items.

Check the injectors for operation sound.

Check the injectors for fuel leakage.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)

Check the positive crankcase ventilation system. (Refer to GROUP 17 ± Emission Control System.)

Check the purge control system. (Refer to GROUP 17 ± Emission Control System.)

Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)
Check the trouble symptom.
NG
Replace the catalytic converter.
Replace the oxygen sensor.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.

MPI ± Troubleshooting13A-47
INSPECTION PROCEDURE 34
MUT-II: Inspection of no initial combustion
MUT-II Data list
16 Voltage of engine-ECU power source (Refer to P.13A-57.)NGCheck the power supply and ignition switch-IG system.
(Refer to P.13A-39, INSPECTION PROCEDURE 23.)
OK
Does the camshaft rotate at the engine cranking?
(When oil filler cap is removed.)NoCheck timing belt for breakage.
Ye s
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
MUT-II Data list
22 Crank angle sensor
OK:Cranking speed is displayed.NoCheck the crank angle sensor system.
(Refer to P.13A-15, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 22.)
OK
MUT-II Actuator test
07 Fuel pump (Refer to P.13A-62.)NGCheck the fuel pump system.
(Refer to P.13A-40, INSPECTION PROCEDURE 24.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
INSPECTION PROCEDURE 35
Ignition system: Inspection of no initial combustion.
Does the engine tachometer display the cranking speed?

Set the tachometer of primary voltage detection type.NGCheck ignition circuit system.
(Refer to P.13A-44, INSPECTION PROCEDURE 30.)
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the crank angle sensor is installed properly.

MPI ± Troubleshooting13A-48
INSPECTION PROCEDURE 36
MUT-II: Check if uncomplete combustion occurs.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS CODE
No
MUT-II Actuator test
07 Fuel pump (Refer to P.13A-62.)NGCheck the fuel pump system.
(Refer to P.13A-40, INSPECTION PROCEDURE 24.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURES FOR DIAGNO-
SIS CODE 21.)
OK
MUT-II Data list
18 Ignition switch-ST (Refer to P.13A-57.)NGCheck the ignition switch-ST system <M/T>.
(Refer to P.13A-41, INSPECTION PROCEDURE 26.)
INSPECTION PROCEDURE 37
Check if hunting occurs.
Clean the throttle body. (Refer to P.13A-78.)
Check and adjust the fixed SAS. (Refer to P.13A-79.)
Check trouble symptom.
NG
Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken air intake hose

Broken vacuum hose

Positive crankcase ventilation valve does not operate.

ENGINE ELECTRICAL ± Charging System16-6
This test determines whether the alternator output
current is normal.
(1) Before the test, always be sure to check the
following.

Alternator installation

Battery (Refer to GROUP 54 ± Battery.)
NOTE
The battery should be slightly discharged.
The load needed by a fully-charged battery
is insufficient for an accurate test.

Alternator drive belt tension (Refer to
GROUP 11 ± On-vehicle Service.)

Fusible link

Abnormal noise from the alternator while
the engine is running.
(2) Turn the ignition switch off.
(3) Disconnect the negative battery cable.
(4) Disconnect the alternator output wire from the
alternator ªBº terminal. Connect a DC test
ammeter with a range of 0 ± 100 A in series
between the ªBº terminal and the disconnected
output wire. (Connect the (+) lead of the
ammeter to the ªBº terminal. Connect the (±)
lead of the ammeter to the disconnected output
wire.)
Caution
Never use clips but tighten bolts and nuts
to connect the line. Otherwise loose
connections (e.g. using clips) will lead to
a serious accident because of high current.
NOTE
An inductive-type ammeter which enables
measurements to be taken without
disconnecting the alternator output wire should
be recommended.
(5) Connect a voltmeter with a range of 0 ± 20 V
between the alternator ªBº terminal and the
earth. (Connect the (+) lead of the voltmeter
to the ªBº terminal, and then connect the (±)
lead of the voltmeter to the earth.)
(6) Connect the negative battery cable.
(7) Connect a tachometer. (Refer to GROUP 11
± On-vehicle Service.)
(8) Leave the hood open.
(9) Check that the reading on the voltmeter is equal
to the battery voltage.
NOTE
If the voltage is 0 V, the cause is probably
an open circuit in the wire or fusible link between
the alternator ªBº terminal and the battery (+)
terminal.(10)Turn the light switch on to turn on headlamps
and then start the engine.
(11) Immediately after setting the headlamps to high
beam and turning the heater blower switch to
the high revolution position, increase the engine
speed to 2,500 r/min and read the maximum
current output value displayed on the ammeter.
Limit: 70% of normal current output
NOTE

For the nominal current output, refer to the
Alternator Specifications.

Because the current from the battery will
soon drop after the engine is started, the
above step should be carried out as quickly
as possible in order to obtain the maximum
current output value.

The current output value will depend on
the electrical load and the temperature of
the alternator body.

If the electrical load is small while testing,
the specified level of current may not be
output even though the alternator is normal.
In such cases, increase the electrical load
by leaving the headlamps turned on for
some time to discharge the battery or by
using the lighting system in another vehicle,
and then test again.

The specified level of current also may not
be output if the temperature of the alternator
body or the ambient temperature is too
high. In such cases, cool the alternator and
then test again.
(12)The reading on the ammeter should be above
the limit value. If the reading is below the limit
value and the alternator output wire is normal,
remove the alternator from the engine and
check the alternator.
(13)Run the engine at idle after the test.
(14)Turn the ignition switch off.
(15)Remove the tachometer.
(16)Disconnect the negative battery cable.
(17)Disconnect the ammeter and voltmeter.
(18)Connect the alternator output wire to the
alternator ªBº terminal.
(19)Connect the negative battery cable.

ABS <2WD> ± Troubleshooting35B-18
Inspection Procedure 7
Brake operation is abnormal.
Probable cause
This varies depending on the driving conditions and the road surface conditions, so
problem diagnosis is difficult. However, if a normal diagnosis code is displayed, carry
out the following inspection.
Improper installation of wheel speed sensor

Incorrect sensor harness contact

Foreign material adhering to wheel speed sensor

Malfunction of wheel speed sensor

Malfunction of rotor

Malfunction of wheel bearing

Malfunction of hydraulic unit

Malfunction of ABS-ECU
OK
Check trouble symptom.NGReplace the ABS-ECU.
OK
Check the following connector.
C-62NG
Repair
NG
Measure at ABS-ECU connector C-62.

Disconnect the connector and
measure at the harness side.

Resistance value between terminals
10-23, 7-20, 8-21 and 9-22
OK:1.2 ± 1.4 kW
(The sensor harness and connector
should be moved while these
inspections are carried out.)NG
Repair
OK
Check trouble symptom.
OK
Check the following connectors.
A-01, A-07, F-01, F-16, D-01, and C-02NG
Repair
OK
Wheel bearing check. (Refer to GROUP
26 and 27 ± On-vehicle Service.)NG
Repair
OK
Rotor check. (Refer to P.35B-40.)NGReplace the rotor.
OK
Hydraulic unit check. (Refer to P.
35B-26.)
OK
Wheel speed sensor output voltage
check. (Refer to P. 35B-24.)NGWheel speed sensor check. (Refer to
P. 35B-39.)NGReplace the wheel speed sensor.
Wheel speed sensor installation check.NG
Repair

ABS <4WD> ± Troubleshooting35C-11
DATA LIST REFERENCE TABLE35201150107
The following items can be read by the MUT-II from the ABS-ECU input data.
1. When the system is normal
Item No.Check itemChecking requirementsNormal value
11Front-right wheel speed sensorPerform a test runVehicle speeds
displayed on the12Front-left wheel speed sensor
dis layed on the
speedometer
and MUTIIare13Rear-right wheel speed sensorand MUT-II are
identical.
14Rear-left wheel speed sensor
16ABS-ECU power supply
voltageIgnition switch power supply voltage and valve
monitor voltage9 ± 16 V
25Free wheel engage switchEngage 4WDON
Engage 2WDOFF
264WD detection switchPlace the transfer lever at 4H.ON
Place the transfer lever at 2H.OFF
27Rear differential lock detection
switch
Turn on the switch.ON
switch
Turn off the switch.OFF
32G-sensor output voltageStop the vehicle.2.4 ± 2.6 V
Perform a test run.Display value
fluctuates with a
mean value of
2.5 V.
33Stop lamp switchDepress the brake pedal.ON
Release the brake pedal.OFF
2. When the ABS-ECU shut off ABS operation.
When the diagnosis system stops the ABS-ECU, the MUT-II display data will be unreliable.
ACTUATOR TEST INSPECTION TABLE35201160056
Refer to GROUP 35B ± Troubleshooting.

SRS ± Sealant/Troubleshooting52B-6
SEALANT52400060015
ItemSpecified sealantRemark
Sensor cable3M ATD Part No. 8625 or equivalentRibbon sealer
TROUBLESHOOTING52400310097
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection Service Points.
DIAGNOSIS FUNCTION52400320083
DIAGNOSIS CODES CHECK
Connect the MUT-II to the diagnosis connector (16-pin) under the instrument under cover, then check
diagnosis codes.
(Refer to GROUP 00 ± How to Use Troubleshooting/Inspection Service Points.)
ERASING DIAGNOSIS CODES
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection Service Points.
INSPECTION CHART FOR DIAGNOSIS CODES52400330123
Inspect according to the inspection chart that is appropriate for the malfunction code.
Code No.Diagnosis itemReference page
11, 12, 13Front impact sensor system52B-7
21, 22Air bag module (squib) system52B-8
31, 32SDU capacitor system52B-9
33*Cranking signal system52B-10
34*Connector lock system52B-11
41*IG1 (A) power circuit system52B-11
42*IG1 (B) power circuit system52B-12
43SRS warning lamp drive circuit system
Lamp does not illuminate*52B-13
SRS warning lamp drive circuit system
Lamp does not switch off52B-14
44SRS warning lamp drive circuit system52B-14
45SDU non-volatile memory (EEPROM) and A/D converter system52B-14
NOTE
(1) *: If the vehicle condition returns to normal, the diagnosis code will be automatically erased, and the SRS warning
lamp will return to normal.
(2) If the vehicle has a discharged battery it will store the fault codes 41 or 42. When these diagnosis codes are displayed,
check the battery.