ECU MITSUBISHI TRITON 1997 Owner's Guide

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-53
INSPECTION PROCEDURE 42
Check the engine-ECU power supply and earth circuit.
OK
Check trouble symptom.
OK
Check the harness wire
between engine-ECU and
ignition switch connector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
4. NG
Check the harness wire between engine-ECU and earth, and repair
if necessary.
5. NG
OK
Check the following
connectors.
C-49, C-50, C-51NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
Check the following connectors.
A-56X, C-19, C-81, C-87NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between engine-ECU and battery, and
repair if necessary.
NG
Check the harness wire between the engine-ECU and control relay,
and repair if necessary.
OK
Check trouble symptom.
2, 3. NG
Check the following
connector. C-53NG
Repair
Measure the engine-ECU connectors, C-49, C-50, C-51.

Disconnect the connector and measure at the harness side
1. Voltage between 62 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 38 and earth
OK:System voltage
3. Voltage between 12, 25 and earth (Ignition switch: ON)
OK:System voltage (when the terminal 38 is earthed)
4. Continuity between 13, 26 and earth
OK:Continuity
5. Voltage between 60 and earth
OK:System voltage1. NGCheck the following
connector. C-88NG
Repair
INSPECTION PROCEDURE 43
Check fuel pump circuit.
Measure at the fuel pump connector F-17.

Disconnect the connector and measure at the harness side.

Continuity between 2 and earth
OK:ContinuityNGCheck the following connectors.
D-02, F-17NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between fuel pump and earth, and repair
if necessary.
OK
Check the following connectors. C-19, D-02, F-17NG
Repair OKCheck trouble symptom.
NG
Check the harness wire between terminal for fuel pump drive and
fuel pump connector.NG
Repair
OK
Replace the fuel pump.

MPI ± Troubleshooting13A-54
INSPECTION PROCEDURE 44
Check the fuel pump drive control circuit.
Measure at the fuel pump relay connector C-54.

Disconnect the connector and measure at the harness side.

Voltage between 4 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between fuel pump relay
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
OK
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.
<Vehicles without immobilizer system>

Voltage between 8 and earth (Ignition switch: ON)
OK:System voltage
<Vehicles with immobilizer system>

Voltage between 22 and earth (Ignition switch: ON)
OK:System voltageNG
Check the following
connector. C-54NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and fuel pump relay
connector, and repair if necessary.
OK
Check the following connector. C-49NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 45
Check air flow sensor (AFS) control circuit.
Measure at the air flow sensor connector A-77.

Disconnect the connector and measure at the harness side.
1. Voltage between 4 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8 ± 5.2 V
3. Continuity between 5 and earth
OK:Continuity1. NGCheck the harness wire between the air flow sensor and control
relay connector, and repair if necessary.
2, 3. NGCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and air flow sensor con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector. A-77NG
Repair
OK
Check trouble symptom.
NG
Replace the air flow sensor.

MPI ± Troubleshooting13A-55
INSPECTION PROCEDURE 46
Check throttle position sensor (TPS) output circuit.
Measure at the engine-ECU connector C-51.

Connect the connector.

Voltage between 64 and earth (Ignition switch: ON)
OK:0.3 ± 1.0 V (Throttle valve at idle position)
4.5 ± 5.5 V (Throttle valve fully open)OKCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NG
Check the following connector. A-47
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and throttle position
sensor connector, and repair if necessary.NG
Repair
INSPECTION PROCEDURE 47
Check injector control circuit
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.

Voltage between 1, 14 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connectors.
A-45, A-46, A-57, A-61NG
Repair
OK
Check trouble symptom.
NG
Check the harness between engine-ECU and injector connector,
and repair if necessary.
OK
Check the following connector. C-49
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Repair

MPI ± Troubleshooting13A-56
INSPECTION PROCEDURE 48
Check ignition coil and power transistor unit circuit.
Check the ignition coil. (Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Check the power transistor unit.
(Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.
1. Voltage between 3 and earth (Ignition switch: ON)
OK: System voltage
2. Voltage between 1 and earth (Engine: Cranking)
OK: 2 ± 7 V1. OKCheck the following
connector. A-65NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the power transistor
unit, and repair if neces-
sary.NG
Repair
NG
As short circuit occurs between power transistor unit and combina-
tion meter (tachometer), check the harness wire, and repair if neces-
sary.
OK
Check the following connectors, and repair if necessary.
A-65, A-70NG
Check the harness wire between the power transistor unit and
ignition coil connector, and repair if necessary. 2. NG
Check the following
connector. C-49NG
Repair
OK
Check trouble symptom. OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.

Disconnect the ignition coil connector.

Continuity between 3 and earth
OK: No continuity
OK
Replace the engine-ECU.

MPI ± Troubleshooting13A-57
DATA LIST REFERENCE TABLE13100890180
Caution
When shifting the select lever to D range, the brakes should be applied so that the vehicle does
not move forward.
NOTE
*1. In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.
*
2. The idle position switch normally turns off when the voltage of the throttle position sensor is 50 ±
100 mV higher than the voltage at the idle position. If the idle position switch turns back on after
the throttle position sensor voltage has been by 100 mV and the throttle valve has been opened,
the idle position switch and the throttle position sensor need to be adjusted.
*3. The injector drive time represents the time when the cranking speed is at 250 r/min or below when
the power supply voltage is 11 V.
*4. In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%
longer than the standard time.
*5. In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes
30 steps greater than the standard value.
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
11Oxygen
sensorEngine:After having
warmed up
Air/fuel mixture is
made leaner when de-
When at 4,000 r/min,
engine is suddenly
decelerated200 mV or lessCode No.
1113A-11
made leaner when de-
celerating, and is made
richer when racing.
When engine is
suddenly raced600 ± 1,000 mV
Engine:After having
warmed up
The oxygen sensor
signal is used to check
the air/fuel mixture
ratio and control
Engine is idling400 mV or less
(Changes)
600 ± 1,000 mV
ratio, and control
condition by the en-
gine-ECU.2,500 r/min400 mV or less
(Changes)
600 ± 1,000 mV
12Air flow
sensor*1
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling22 ± 48 Hz
<4G63>
19 ± 45 Hz
<4G64>±±
accessories: OFF

Transmission:
Neutral (A/T:
P range)2,500 r/min80 ± 120 Hz
<4G63>
67 ± 107 Hz
<4G64>
Engine is racedFrequency
increases in
response to
racing

MPI ± Troubleshooting13A-68
Terminal No. Normal condition (Check condition)Inspection item
4±12Stepper motor coil (A1)28 ± 33 W (At 20
C)
17 ± 12Stepper motor coil (A2)
5±12Stepper motor coil (B1)
18 ± 12Stepper motor coil (B2)
6±12EGR control solenoid valve36 ± 44 W (At 20
C)
9±12Purge control solenoid valve36 ± 44 W (At 20
C)
13 ± Body earthEngine-ECU earthContinuity (0W)
26 ±Body earthEngine-ECU earth
35 ± 12Oxygen sensor heaterApprox. 12 W (At 20
C)
52 ± 72Intake air temperature sensor5.3 ± 6.7 kW (When intake air temperature is 0
C)
2.3 ± 3.0 kW (When intake air temperature is 20
C)
1.0 ± 1.5 kW (When intake air temperature is 40
C)
0.30 ± 0.42 kW (When intake air temperature is 80
C)
63 ± 72Engine coolant temperature sensor5.1 ± 6.5 kW (When coolant temperature is 0
C)
2.1 ± 2.7 kW (When coolant temperature is 20
C)
0.9 ± 1.3 kW (When coolant temperature is 40
C)
0.26 ± 0.36 kW (When coolant temperature is 80
C)
67 ± 72Idle position switchContinuity (when throttle valve is at idle position)
No continuity (when throttle valve is slightly open)
71 ±Body earthInhibitor switch <A/T>Continuity (when select lever is at P or N)
No continuity (when select lever is at D, 2, L or R)

MANUAL TRANSMISSION ± 4WD Indicator-ECU22-16
Terminal No.Inspection itemInspection condition
1: Ignition switchInspection condition
2: Transfer lever positionTerminal voltage
1Free wheel engage
switch
ON2HSystem voltage
switch
4H*10 V
24WD detection
switch
ON2HSystem voltage
switch
4H, 4L0 V
3Ignition switch (IG1)OFF±0 V
ON±System voltage
5Free wheel differen-
tial indicator lamp
ON2HSystem voltage
tial indicator lam
4H*10 V
6HI/LOW detection
switchONShifting from 4H to 4L
or vice versaSystem voltage
2H, 4H, 4L0 V
7Free wheel clutch
changeover solenoid
ON4H, 4L0 V
changeover solenoid
valve2H*2System voltage
104WD Indicator lampON2H0 V
4H, 4LSystem voltage
NOTE
*1: When vehicle has been moved once.
*2: Shift the lever from 4H to 2H, and then turn the ignition switch to OFF and then back to ON.

35B-2
Bleeding 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Fluid Level Sensor Check
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . . . .
Load Sensing Spring Length Check and
Adjustment Refer to GROUP 35A. . . . . . . . . . . . . . .
Load Sensing Proportioning Valve Function
Test Refer to GROUP 35A. . . . . . . . . . . . . . . . . . . . .
Disc Brake Pad Check and Replacement 23. . . . .
Front Disc Brake Rotor Check
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining Thickness Check
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Drum Inside Diameter Check
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Lining and Brake Drum Connection Check
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . . . .
Wheel Speed Sensor Output Voltage Check
24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hydraulic Unit Check 26. . . . . . . . . . . . . . . . . . . . . . . .
Solenoid Valve Check 27. . . . . . . . . . . . . . . . . . . . . . .
Motor Operation Check 27. . . . . . . . . . . . . . . . . . . . . . Motor Relay and Valve Relay Continuity
Check 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remedy for a Flat Battery 28. . . . . . . . . . . . . . . . . . .
BRAKE PEDAL Refer to GROUP 35A. . . . . . . .
MASTER CYLINDER AND BRAKE
BOOSTER 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOAD SENSING PROPORTIONING VALVE
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . .
FRONT DISC BRAKE 32. . . . . . . . . . . . . . . . . . . . .
REAR DRUM BRAKE
Refer to GROUP 35A . . . . . . . . . . . . . . . . . . . . . . . .
HYDRAULIC UNIT 37. . . . . . . . . . . . . . . . . . . . . . . . .
WHEEL SPEED SENSOR 39. . . . . . . . . . . . . . . . . .
ABS-ECU 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ABS <2WD> ± Troubleshooting35B-6
INSPECTION CHART FOR DIAGNOSIS CODES35201130156
Inspect according to the inspection chart that is appropriate for the malfunction code.
Diagnosis
code No.Inspection itemDiagnosis contentReference page
11Front right wheel speed sensorOpen or short circuit35B-7
12Front left wheel speed sensor
13Rear right wheel speed sensor
14Rear left wheel speed sensor
15Wheel speed sensorAbnormal output signal35B-8
16Power supply system35B-8
21Front right wheel speed sensorAbnormal35B-7
22Front left wheel speed sensor
23Rear right wheel speed sensor
24Rear left wheel speed sensor
33Stop lamp switch system35B-9
41Front right solenoid valve35B-10
42Front left solenoid valve
43Rear solenoid valve
51Valve relay35B-11
53Motor relay, motor35B-12
63ABS-ECU35B-41
(Replace the ABS-ECU)
64
(Re lace the ABS-ECU)