1997 MITSUBISHI TRITON check engine

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 .
(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.

MPI ± Troubleshooting13A-49
INSPECTION PROCEDURE 38
MUT-II: Check if idling speed is unstable.
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
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
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 Actuator test
08 Purge control solenoid valve (Refer to P.13A-62.)NGCheck the purge control solenoid valve system
(Refer to P.13A-45, INSPECTION PROCEDURE 32.)
MUT-II Data list
11 Oxygen sensor
OK:600 ±1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ±400 mV and 600 ±1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system.

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13A-57.)NGCheck the power steering
fluid pressure switch sys-
tem. (Refer to P.13A-43,
INSPECTION PROCE-
DURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13A-57.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13A-43. INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
29 Inhibitor switch (Refer to P.13A-57.)NGCheck the ignition switch-ST and inhibitor switch system.
(Refer to P.13A-42, INSPECTION PROCEDURE 27.)
OK
MUT-II Data list
45 ISC Servo position (Refer to P.13A-57.)NGAdjust the basic idle speed. (Refer to P.13A-79.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system. (Refer to P.13A-46,
INSPECTION PROCEDURE 33.)

MPI ± Troubleshooting13A-50
INSPECTION PROCEDURE 39
MUT-II: Engine stalling inspection when the engine is warmed up and idling.
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
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION 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
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
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13A-57.)NGCheck the power steering
fluid pressure switch sys-
tem. (Refer to P.13A-43,
INSPECTION PROCE-
DURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13A-57.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13A-43, INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
29 Inhibitor switch (Refer to P.13A-57.)NGCheck the ignition switch-ST and inhibitor switch system.
(Refer to P.13A-42, INSPECTION PROCEDURE 27.)
OK
MUT-II Data list
45 ISC servo position (Refer to P.13A-57.)NGAdjust the basic idle speed. (Refer to P.13A-79.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system. (Refer to P.13A-46,
INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)

MPI ± Troubleshooting13A-51
INSPECTION PROCEDURE 40
MUT-II: Check if hesitation, sug, stumble or poor acceleration occurs.
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
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION 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
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 DIAGNOS-
TIC CODE 21.)
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 Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

MPI ± Troubleshooting13A-52
INSPECTION PROCEDURE 41
MUT-II: Check if surge occurs.
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
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION 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
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
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 Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.s13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

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.


Voltage between 8 and earth (Ignition switch: ON)
OK:System voltage


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