1999 MITSUBISHI LANCER EVOLUTION VI Evo 7 workshop manual

MPI – Troubleshooting13-38
INSPECTION PROCEDURE 26
Idle position switch system
Probable cause
The idle position switch inputs the condition of the accelerator pedal, i.e. whether
it is depressed or released (HIGH/LOW), to the engine-ECU.
The engine-ECU controls the idle speed control servo based on this input.
Maladjustment of the accelerator cable

Maladjustment of the fixed SAS

Maladjustment of the idle position switch and throttle
position sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Check the idle position switch. (Refer to P.13-30.)*NGReplace the throttle position sensor.
OK
Measure at the throttle position sensor connector A-16.

Disconnect the connector, and measure at the harness side.

Voltage between 3 and earth (Ignition switch: ON)
OK:4 V or higher

Continuity between 4 and earth
OK:ContinuityNGCheck the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and throttle position
sensor connector.
OK
Replace the engine-ECU.
NG
Repair
OK
Check the following
connector: A-16NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).
INSPECTION PROCEDURE 27
Ignition switch-ST system
Probable cause
The ignition switch-ST inputs a HIGH signal to the engine-ECU while the engine is
cranking.
The engine-ECU controls fuel injection, etc. during starting based on this input.
Malfunction of ignition switch

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Measure at the engine-ECU connector B-62.

Disconnect the connector, and measure at the harness side.
1. Voltage between 71 and earth (Ignition switch: START)
OK:8V
2. Continuity between 91 and earth
OK:Continuity1. NGCheck the following
connector: B-64NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween the engine-ECU
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
2. NG
Check the harness wire between engine-ECU connector (terminal
No.91) and earth, and repair if necessary.
OK
Check the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.

MPI – Troubleshooting13-42
INSPECTION PROCEDURE 31
Oxygen sensor system
Probable cause
When CO or HC concentration is too high, the malfunction of the parts shown at
right may be the cause.

The oxygen sensor detects the density of oxygen in exhaust gas and inputs it
to the engine-ECU after converting into a voltage signal.

The engine-ECU controls the fuel injection amount based on this signal such that
the stoichiometric air/fuel mixture ratio can be obtained.
Malfunction of oxygen sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
OK
Replace the engine-ECU.
Check the harness wire between
engine-ECU and oxygen sensor connector.NG
Repair
NG
OK
Check trouble symptom.
OK
Replace the engine-ECU.
NG
Check the harness wire between
engine-ECU and oxygen sensor connector.NG
Repair
OK
Check trouble symptom.
OK
Check the following connector: A-63NG
Repair
OK
Measure at the oxygen sensor connector A-63.

Disconnect the connector, and measure at the harness side.

Continuity between 2 and earth
OK:ContinuityNGCheck the following connector: B-62NG
Repair
Check the oxygen sensor. (Refer to P.13-32.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-43
INSPECTION PROCEDURE 31
Oxygen sensor system
Probable cause
When CO or HC concentration is too high, the malfunction of the parts shown at
right may be the cause.

The oxygen sensor detects the density of oxygen in exhaust gas and inputs it
to the engine-ECU after converting into a voltage signal.

The engine-ECU controls the fuel injection amount based on this signal such that
the stoichiometric air/fuel mixture ratio can be obtained.
Malfunction of oxygen sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
OK
Replace the engine-ECU.
NG
Check the harness wire between oxygen sensor, engine-ECU,
and repair if necessary.
OK
Check trouble symptom.
NG
Check the harness wire between oxygen sensor and engine-ECU,
and repair if necessary.
OK
Check trouble symptom.
OK
Check trouble symptom.NGCheck the harness wire between
engine-ECU and oxygen sensor.NG
Repair
OK
Check the following connector: B-61NG
Repair
OK
NG
Measure at the engine-ECU connector B-61.

Disconnect the connector, and measure at the harness side.

Voltage between 60 and earth
(Ignition switch: ON)
OK:System voltageCheck the following connector: A-63NG
Repair 1. NG
Check the harness wire between oxygen sensor and control relay,
and repair if necessary.
OK
2. NG
Measure at the oxygen sensor connector A-63.

Disconnect the connector, and measure at the harness side.
1. Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltage
2. Continuity between 2 and earth
OK:Continuity
Check the following connector: B-62NG
Repair
Check the oxygen sensor. (Refer to P.13-32)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-45
INSPECTION PROCEDURE 34
Fuel pressure control valve system
Probable cause
The fuel pressure control valve switches the pressure introduction into the fuel pressure
regulator between the intake manifold and atmosphere.
Malfunction of solenoid valve

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NGReplace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
OK
Check the following connector: B-59NG
Repair
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between 3 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector: A-12NG
Repair NG
Check the harness wire between control relay and solenoid valve
connector, and repair if necessary.
OK
Measure at the fuel pressure control valve connector A-12.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltage
Check the fuel pressure control valve.NG
Replace
INSPECTION PROCEDURE 35
Waste gate solenoid valve
Probable cause
The waste gate solenoid valve controls the boost pressure introduced into the waste
gate actuator in the turbocharger.
Malfunction of solenoid valve

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NGReplace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
OK
Check the following connector: B-59NG
Repair
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between 11 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector: A-23NG
Repair NG
Check the harness wire between control relay and solenoid valve
connector, and repair if necessary.
OK
Measure at the waste gate solenoid valve connector A-23.

Disconnect the connector, and measure at the harness side.

Voltage between 2 and earth
(Ignition switch: ON)
OK:System voltage
Check the waste gate solenoid valve.
(Refer to Group 15 – On-vehicle service.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-46
INSPECTION PROCEDURE 36
Secondary air control solenoid valve system
Probable cause
The secondary air control solenoid valve switches the pressure introduction into the
secondary air valve between the intake manifold and atmosphere.
Malfunction of solenoid valve

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NGReplace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
NG
Check the harness wire between control relay and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
OK
Check the following connector: B-59NG
Repair
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between 6 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connectors:
A-127, A-88NG
Repair
OK
Measure at the secondary air control solenoid connector A-127.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector: A-88NG
Repair
Check the secondary air control solenoid valve.
(Refer to Group 15 – INTAKE AND EXHAUST.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-48
INSPECTION PROCEDURE 39
MUT-II: Check if uncomplete combustion occurs.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
MUT-II Actuator test
07 Fuel pump (Refer to P.13-61.)NGCheck the fuel pump system.
(Refer to P.13-36, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURES FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
18 Ignition switch-ST (Refer to P.13-57.)NGCheck the ignition switch-ST system.
(Refer to P.13-38, INSPECTION PROCEDURE 27.)
INSPECTION PROCEDURE 40
Check if hunting occurs.
Clean the throttle body.
Check and adjust the fixed SAS. (Refer to P.13-30.)*
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.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-49
INSPECTION PROCEDURE 41
MUT-II: Check if idling speed is unstable.
OK
MUT-II Data list
45 ISC servo position (Refer to P.13-60.)NGAdjust the basic idle speed. (Refer to P.13-30.)*
MUT-II Data list
28 A/C switch (Refer to P.13-58.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13-39. INSPECTION PROCEDURE 29.)
OK
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13-58)NGCheck the power steering fluid pressure switch system.
(Refer to P.13-39, INSPECTION PROCEDURE 28.)
1. 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
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.13-30.)*
OK
MUT-II Data list
11 Oxygen sensor
OK:600–1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13-42, INSPECTION
PROCEDURE 31.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-21.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-50
INSPECTION PROCEDURE 42
MUT-II: Engine stalling inspection when the engine is warmed up and idling.
OK
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600–1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13-42, INSPECTION
PROCEDURE 31.)
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.13-30.)*
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13-58.)NGCheck the power steering fluid pressure switch system.
(Refer to P.13-39, INSPECTION PROCEDURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13-58.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13-39, INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
45 ISC servo position (Refer to P.13-60.)NGAdjust the basic idle speed. (Refer to P.13-30.)*
1. 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.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).