Mitsubishi Lancer Evolution VI. Manual - part 37

MPI  – 

Troubleshooting

13-36

INSPECTION PROCEDURE 25 <EVOLUTION-IV, EVOLUTION-V>

Fuel pump system

Probable cause

The engine-ECU turns the control relay ON when the engine is cranking or running,
and this supplies power to drive the fuel pump.

D

Malfunction of the fuel pump relay

D

Malfunction of the fuel pump

D

Improper connector contact, open or short-circuited
harness wire

D

Malfunction of the engine-ECU

OK

Check the harness wire between resistor connector and fuel pump
drive terminal and between fuel pump relay No.2 connector and
fuel pump drive terminal, and repair if necessary.

OK

Check the resistor. (Refer to P.13-34.)*

NG

Replace

OK

Measure at the resistor connector A-124.

D

Disconnect the connector.

D

Voltage between 1 and earth

D

MUT-

II

 Actuator test: Fuel pump relay No.2 drive

OK: System voltage

NG

Check the harness wire between fuel pump relay No.2 and resistor
connector, and repair if necessary.

OK

Measure at the engine-ECU connector B-60.

D

Connect the connector.

D

Voltage between 39 and earth

D

MUT-

II

 Actuator test: Fuel pump drive

OK: System voltage

NG

Check the harness wire between fuel pump relay No.2 and
engine-ECU connector, and repair if necessary.

NG

Check the harness wire between fuel pump relay and fuel pump
relay No.2 connector, and repair if necessary.

OK

Measure at the fuel pump relay No.2 connector A-123.

D

Disconnect the connector.

D

Voltage between each of 3 and 5 and earth

D

MUT-

II

 Actuator test: Fuel pump drive

OK: System voltage

OK

Check the fuel pump relay No.2. (Refer to P.13-68)

NG

Replace

OK

Check the following connectors:
D-18, D-04, B-64, A-124, A-123, B-59, B-60

NG

Repair

OK

Measure at the fuel pump relay connector B-28.

D

Connect the connector.

D

Voltage between 1 and earth

D

MUT-

II

 Actuator test: Fuel pump drive

OK: System voltage

NG

Check the fuel pump drive control circuit. 
(Refer to P.13-54, INSPECTION PROCEDURE 47.)

OK

Check the fuel pump relay. (Refer to P.13-68.)

NG

Replace

Check the fuel pump operation by applying the system voltage
to the fuel pump drive terminal.

NG

Check the fuel pump circuit. 
(Refer to P.13-53, INSPECTION PROCEDURE 46.)

NOTE
*:

Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI  – 

Troubleshooting

13-37

INSPECTION PROCEDURE 25 <EVOLUTION-VI>

Fuel pump system

Probable cause

D

The engine-ECU turns the fuel pump relay ON when the engine is cranking or
running, and this supplies power to drive the fuel pump.

D

The engine-ECU supplies power to the fuel pump through the resistor at low load
operations. It supplies power directly to the fuel pump at high load operations
to increase the pump output.

D

Malfunction of the fuel pump relay

D

Malfunction of the fuel pump relay No.2

D

Malfunction of the fuel pump

D

Malfunction of fuel pump resistor

D

Improper connector contact, open or short-circuited
harness wire

D

Malfunction of engine-ECU

OK

Check the fuel pump drive control circuit. 
(Refer to P.13-54, INSPECTION PROCEDURE 47.)

Check the harness wire between fuel pump
relay No.2 and fuel pump relay connector,
and repair if necessary.

NG

Repair

NG

OK

Check trouble symptom.

NG

Check the harness wire between fuel pump relay No.2 and
engine-ECU connector, and repair if necessary.

OK

Check trouble symptom.

NG

Replace the engine-ECU.

OK

Check trouble symptom.

OK

Check the following connector: B-60

NG

Repair

OK

Measure at the engine-ECU connector B-60.

D

Disconnect the connector, and measure at the harness side.

D

Voltage between 39 and earth

D

MUT-

II

 Actuator test: 07 Fuel pump

OK: System voltage

NG

Check the following connector: A-123

NG

Repair

NG

Check the harness wire between fuel pump resistor and fuel pump
relay connector, and repair if necessary.

OK

Measure at the fuel pump resistor connector A-124.

D

Disconnect the connector, and measure at the harness side.

D

Voltage between 1 and earth

D

MUT-

II

 Actuator test: 13 Fuel pump relay No.2

OK: System voltage

OK

Measure at the fuel pump relay No.2 connector A-123.

D

Disconnect the connector, and measure at the harness side.

D

Disconnect the fuel pump resistor connector.

D

Voltage between each of 1 and 3 and earth

D

MUT-

II

 Actuator test: 07 Fuel pump drive

OK: System voltage

NG

Check the following connector: B-28

NG

Repair

OK

Check the fuel pump relay No.2 and fuel pump resistor. 
(Refer to P.13-68.)

NG

Replace

OK

Check the fuel pump relay. (Refer to P.13-68.)

NG

Replace

Check the harness wire between fuel pump resistor and fuel pump
connector, and repair if necessary.

OK

Perform fuel pump operation check.

D

Disconnect the fuel pump resistor connector.

D

Apply system voltage to terminal No.2 of the harness side
connector.
OK: Fuel pump operates.

NG

Perform fuel pump operation check.

D

Disconnect the fuel pump relay No.2 connector.

D

Apply system voltage to terminal No.2 of the harness side
connector.
OK: Fuel pump operates.

NG

Check the fuel pump circuit. 
(Refer to P.13-54, INSPECTION PROCEDURE 46.)

MPI  – 

Troubleshooting

13-38

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.

D

Maladjustment of the accelerator cable

D

Maladjustment of the fixed SAS

D

Maladjustment of the idle position switch and throttle
position sensor

D

Improper connector contact, open or short-circuited
harness wire

D

Malfunction of the engine-ECU

Check the idle position switch. (Refer to P.13-30.)*

NG

Replace the throttle position sensor.

OK

Measure at the throttle position sensor connector A-16.

D

Disconnect the connector, and measure at the harness side.

D

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

D

Continuity between 4 and earth
OK: Continuity

NG

Check the following
connector: B-62

NG

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-16

NG

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.

D

Malfunction of ignition switch

D

Improper connector contact, open or short-circuited
harness wire

D

Malfunction of the engine-ECU

Measure at the engine-ECU connector B-62.

D

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: Continuity

1. NG

Check the following
connector: B-64

NG

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-62

NG

Repair

OK

Check trouble symptom.

NG

Replace the engine-ECU.

MPI  – 

Troubleshooting

13-39

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.

D

Malfunction of power steering fluid pressure switch

D

Improper connector contact, open or short-circuited
harness wire

D

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.

D

Disconnect the connector, and measure at the harness side.

D

Voltage between 1 and earth (Ignition switch: ON)
OK: System voltage

NG

Check the following
connectors: A-28, B-60

NG

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-101

NG

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.

D

Malfunction of A/C control system

D

Malfunction of A/C switch

D

Improper connector contact, open or short-circuited
harness wire

D

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.

D

Disconnect the connector, and measure at the harness side.

D

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

D

Short-circuit between 22 and earth
(Ignition switch: ON, A/C switch: ON)
OK: A/C compressor clutch turns on.

NG

Check the A/C system. (Refer to GROUP 55 – On-vehicle Service.)

OK

Check the following
connectors: B-59, B-60

NG

Replace

OK

Check trouble symptom.

NG

Replace the engine-ECU.