MITSUBISHI LANCER EVOLUTION VI 1999 Workshop Manual

MPI – Troubleshooting13-39
INSPECTION PROCEDURE 28
Power steering fluid pressure switch system
Probable cause
The presence or absence of power steering load is input to the engine-ECU.
The engine-ECU controls the idle speed control (ISC) servo based on this input.
Malfunction of power steering fluid pressure switch

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Check the power steering fluid pressure switch.NG
Replace
OK
Measure at the power steering fluid pressure switch connector
A-101.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connectors: A-28, B-60NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween engine-ECU and
power steering fluid pres-
sure switch connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following
connector: A-101NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 29
A/C switch and A/C relay system
Probable cause
When an A/C ON signal is input to the engine-ECU, the engine-ECU carries out
control of the idle speed control (ISC) servo, and also operates the A/C compressor
magnetic clutch.
Malfunction of A/C control system

Malfunction of A/C switch

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Check the A/C compressor relay.
(Refer to GROUP 55 – On-vehicle Service.)NG
Replace
OK
Measure at the engine-ECU connectors B-59, B-60.

Disconnect the connector, and measure at the harness side.

Voltage between 22 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK:System voltage

Short-circuit between 22 and earth
(Ignition switch: ON, A/C switch: ON)
OK:A/C compressor clutch turns on.NGCheck the A/C system. (Refer to GROUP 55 – On-vehicle Service.)
OKCheck the following
connectors: B-59, B-60NG
Replace
OK
Check trouble symptom.
NG
Replace the engine-ECU.

MPI – Troubleshooting13-40
INSPECTION PROCEDURE 30
Fan motor relay system (Radiator fan, A/C condenser fan)
Probable cause
The engine-ECU turns on/off the built-in power transistor to control the fan motor
relay.
Malfunction of the fan motor relay

Malfunction of the fan motor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NG

Check the radiator fan circuit.

Check the A/C condenser fan circuit.
(Refer to Electrical Wirings.)
NG
Replace the engine-ECU.
OK
Check trouble symptom.
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between each of 20 and 21 and earth
(Ignition switch: ON)
OK:System voltage

Short the terminal 21 to earth.
(Ignition switch: ON)
OK:Fan operates at low speed.

Short the terminals 20 and 21 to earth.
(Ignition switch: ON)
OK:Fan operates at high speed.OKCheck the following connector: B-59NG
Repair

MPI – Troubleshooting13-41
INSPECTION PROCEDURE 30
Fan motor relay system (Radiator fan, A/C condenser fan)
Probable cause
The engine-ECU turns on/off the built-in power transistor to control the fan motor
relay.
Malfunction of the fan motor relay

Malfunction of the fan motor

Malfunction of thermostat

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NG
Check the engine coolant temperature sensor. (Refer to P.13-10,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
Replace the engine-ECU.
NG
MUT-II Data list
21 Engine coolant temperature sensor
OK:The engine coolant temperature agrees with the reading
of MUT-II when measured with the engine idling in warm
condition.OKCheck the thermostat.NG
Replace
OK
Check trouble symptom.
OK
Check the following connector: B-60NG
Repair NG
Check the A/C condenser fan circuit. (Refer to Electrical Wirings.)
NG
Measure at the engine-ECU connector B-60.

Disconnect the connector, and measure at the harness side.

Check the A/C condenser fan for operating condition.
(Ignition switch: ON)
OK:A/C condenser fan is stationary.

Voltage between each of 32 and 34 and earth
(Ignition switch: ON)
OK:System voltage

Short the terminal 32 to earth. (Ignition switch: ON)
OK:A/C condenser fan operates at high speed.

Short the terminal 34 to earth. (Ignition switch: ON)
OK:A/C condenser fan operates at low speed.
Check trouble symptom.
OK
OK
Check the following connector: B-59NG
Repair
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Check the radiator fan for operating condition.
(Ignition switch: ON)
OK:Radiator fan is stationary.

Voltage between each of 20 and 21 and earth
(Ignition switch: ON)
OK:System voltage

Short the terminal 20 to earth.
(Ignition switch: ON)
OK:Radiator fan operates at high speed.

Short the terminal 21 to earth.
(Ignition switch: ON)
OK:Radiator fan operates at low speed.NGCheck the radiator fan circuit. (Refer to Electrical Wirings.)

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 – Troubleshooting13-44
INSPECTION PROCEDURE 32
Ignition circuit system
Probable cause
The engine-ECU interrupts the ignition coil primary current by turning the power transistor
inside the engine-ECU ON and OFF.
Malfunction of ignition switch.

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Measure at the ignition coil connectors A-110, A-111.

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:Continuity1. NGCheck the following
connectors: B-65, B-76NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between ignition coil and
ignition switch connector.NG
Repair
OK
Check the ignition switch. 2. NG
Check the harness wire between ignition coil connector and earth,
and repair if necessary.
OK
Check the following
connectors:
A-110, A-111NG
Repair
OK
Check trouble symptom.NGCheck ignition coil and power transistor unit system. (Refer to
P.13-16, INSPECTION PROCEDURE FOR DIAGNOSIS CODE
44.)
INSPECTION PROCEDURE 33
Idle speed control (ISC) servo (Stepper motor) system
Probable cause
The engine-ECU controls the intake air volume during idling by opening and closing
the servo valve located in the bypass air passage.
Malfunction of ISC servo

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Check the ISC servo.NG
Replace
OK
Measure at the ISC servo connector A-18.

Disconnect the connector and measure at the harness side.

Voltage between 2 and earth, and 5 and earth (Ignition switch:
ON)
OK:System voltageNGCheck the harness wire between control relay and ISC servo con-
nector, and repair if necessary.
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, measure at the harness side.

Voltage between each of 4, 5, 17, 18 and earth (Ignition switch:
ON)
OK:System voltageNGCheck the following
connector: A-18NG
Repair
OK
Check trouble symptom.
NG
Check harness wire between engine-ECU and ISC servo connector,
and repair if necessary.
OK
Check the following
connector: B-59NG
Repair
OK
Check trouble symptom.NGReplace the engine-ECU.

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 – Troubleshooting13-47
INSPECTION PROCEDURE 37
MUT-II: Inspection of no initial combustion
MUT-II Data list
16 engine-ECU power supply voltage (Refer to P.13-57.)NGCheck the power supply and ignition switch-IG system.
(Refer to P.13-35, INSPECTION PROCEDURE 24.)
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.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
MUT-II Data list
22 Crank angle sensor
OK:Cranking speed is displayed.NGCheck the crank angle sensor system.
(Refer to P.13-11, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 22.)
OK
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 PROCEDURE FOR DIAGNOSIS
CODE 21.)
INSPECTION PROCEDURE 38
Ignition system: Inspection of no initial combustion.
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the crank angle sensor and the timing belt cover are
installed properly.
NGCheck the ignition circuit system.
(Refer to P.13-44, INSPECTION PROCEDURE 32.)Check by connecting a timing light to the spark plug cable.
OK:Timing light flashes during cranking.

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).