Mitsubishi Montero (2004+). Manual — part 358

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-919

.

AK201553

1

2

3

4

5

G-04(GR)

AB

CONNECTOR: G-04

HARNESS
CONNECTOR:
COMPONENT SIDE

AK201038

CONNECTOR: D-132

AB

PCM

D-132(GR)

AK201041AD

CONNECTOR: D-208

D-208

AK201176

B-19X

B-24X

AB

CONNECTORS: B-19X, B-24X

FUEL PUMP
RELAY (1)

FUEL PUMP
RELAY (2)

AK201045

D-204

AB

CONNECTOR: D-204

AK201294

D-221

AB

CONNECTOR: D-221

AK201060

E-111

AB

CONNECTOR: E-111

AK201055

CONNECTOR: D-111

D-111

AB

AK304350

F-07 (B)

AB

CONNECTOR: F-07

AK201351

A-05(B)

AB

CONNECTOR: A-05

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-920

CIRCUIT OPERATION

• Battery positive voltage is applied to the fuel

pump relay 2 (terminal No. 4) from the ignition
switch-IG.
Ground is provided through (terminal No. 2) to
chassis ground.

• When the ignition switch is turned to the "ON"

position, the fuel pump relay 2 turns ON.

• A battery positive voltage is applied on the fuel

pump relay 1 (terminal No. 2) from the ignition
switch-IG.

• During cranking and while the engine is running,

the PCM turns the power transistor in the PCM
ON to ground the fuel pump relay 1 coil. With this,
the fuel pump relay 1 turns ON, and the battery
positive voltage is supplied to the fuel pump from
the fuel pump relay 1 (terminal No. 1), via fuel
pump relay 2.

.

TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)

• Malfunction of the fuel pump relay.

• Malfunction of the fuel pump.

• Improper connector contact, open or

short-circuited harness wire.

• Malfunction of the PCM.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, check actuator test
item 07: Fuel Pump.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the actuator test mode for item

07, Fuel Pump.

• An operation sound of the fuel pump should be heard.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the fuel pump operating properly?

YES : That this malfunction is intermittent. Refer to GROUP

00, How to Use Troubleshooting/Inspection Service
Points

P.00-6

.

NO : Go to Step 2.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-921

STEP 2. Check connector B-19X at fuel pump relay 1 and
connector B-24X at fuel pump relay 2 for damage.
Q: Is the connector in good condition?

YES : Go to Step 3.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then confirm that the

malfunction symptom is eliminated.

STEP 3. Check the fuel pump relay 1 and 2.
(1) Remove the fuel pump relay.

(2) Check for continuity between the fuel pump relay terminal

No. 2 and No. 4.

• There should be continuity. (approximately 70 ohms)

(3) Use jumper wires to connect fuel pump relay terminal No. 4

to the positive battery terminal and terminal No. 2 to the
negative battery terminal.

(4) Check for continuity between the fuel pump relay terminal

No. 1 and No. 3 while connecting and disconnecting the
jumper wire at the negative battery terminal.

• Should be less than 2 ohms. (Negative battery terminal

connected)

• Should be open loop. (Negative battery terminal discon-

nected)

(5) Install the fuel pump relay.
Q: Is the resistance normal?

YES : Go to Step 4.
NO : Replace the fuel pump relay. Then confirm that the

malfunction symptom is eliminated.

AK201178

2 1

3

4

B-19X

B-24X

AB

CONNECTORS: B-19X, B-24X

HARNESS
CONNECTOR:
COMPONENT SIDE

AK201178

2 1

3

4

B-19X

B-24X

AB

CONNECTORS: B-19X, B-24X

HARNESS
CONNECTOR:
COMPONENT SIDE

1

2

3

4

AK201380AF

FUEL PUMP
RELAY SIDE
CONNECTOR

1

2

3

4

AK201381AF

FUEL PUMP
RELAY SIDE
CONNECTOR

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-922

STEP 4. Measure the power supply voltage at fuel pump
relay 1 harness side connector B-19X.
(1) Disconnect the connector B-19X and measure at the

harness side.

(2) Measure the voltage between terminal No. 3 and ground.

• Voltage should be battery positive voltage.

Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 5.
NO : Check harness connector A-05 at intermediate

connector for damage, and repair or replace as
required. Refer to GROUP 00E, Harness Connector
Inspection

P.00E-2

. If intermediate connectors are in

good condition, repair harness wire between fuse box
(fuse 6) and fuel pump relay 1 connector B-19X
(terminal No. 3) because of open circuit. Then confirm
that the malfunction symptom is eliminated.

STEP 5. Measure the power supply voltage at fuel pump
relay 2 harness side connector B-24X.
(1) Disconnect the connector B-24X and measure at the

harness side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 4 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 6.

AK201175

2 1

3

4

B-19X

AB

CONNECTOR: B-19X

HARNESS
CONNECTOR:
COMPONENT SIDE

2 1

3

4

AK201382AF

B-19X HARNESS
CONNECTOR:
COMPONENT SIDE

AK201177

2 1

3

4

B-24X

AB

CONNECTOR: B-24X

HARNESS
CONNECTOR:
COMPONENT SIDE

2 1

3

4

AK201383AD

B-24X HARNESS
CONNECTOR:
COMPONENT SIDE