Mitsubishi Montero (2004+). Manual - part 254

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-503

STEP 3. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− Procedure 5 − Exhaust Gas 

Recirculation (EGR) System Monitor 

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0401 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-504

DTC P0403: Exhaust Gas Reculation Control Circuit

WHITE-

BLA

C

K

WHITE-

BLA

C

K

RED

GREEN-BLA

C

K

RED

RED

GREEN-RED

BLUE-ORANGE

BLA

CK-YELLO

W

AK201148

MFI RELAY

BATTERY

3

2

1

4

3 4

1 2

B-22X

B-56

(MU802056)

2

5

3

12

19

26

1

3

4

6

EGR
VALVE

POWERTRAIN
CONTROL
MODULE (PCM)

EGR Valve Circuit

1

2 3

4

5 6

1

2

3

5

6 7 8 9

4

20

21 22

232425

2627

10111213

14 15

16 1718

19

D-132

(MU803802)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-505

.

CIRCUIT OPERATION

• The EGR valve power is supplied from the MFI 

relay (terminal No. 1).

• The PCM (terminals No. 3, No. 12, No. 19, No. 

26) drives the stepper motor by sequentially turn-
ing "ON" the power transistors in the PCM and 
providing ground to the idle air control motor (ter-
minal No. 1, No. 3, No. 4, No. 6).

.

TECHNICAL DESCRIPTION

• To judge if there is open circuit in the EGR valve 

(stepper motor) drive circuit, PCM measure the 
surge voltage of the EGR valve motor coil.

.

DESCRIPTIONS OF MONITOR METHODS
Off-surge does not occur after stepper motor is oper-

ated on to off.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• EGR stepper motor monitor

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

• Accelerator pedal position sensor

• Manifold absolute pressure sensor

.

AK200966

EGR 
VALVE

AB

B-56(GR)

CONNECTOR: B-56

AK201038

CONNECTOR: D-132

AB

PCM

D-132(GR)

AK201039

MFI RELAY

B-22X

AB

CONNECTOR: B-22X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-506

DTC SET CONDITIONS 

Logic Flow Chart

.

Check Conditions

• Battery positive voltage is higher than 10.3 volts.

• In a few seconds, just after ignition switch is 

turned to the "ON" position from the 
"LOCK"(OFF) position. (While EGR valve is ini-
tialized.)

Judgment Criteria

• The EGR valve motor coil surge voltage (battery 

positive voltage +2 volts) is not detected for 3 
seconds.

Check Conditions

• Battery positive voltage is higher than 10.3 volts.

• EGR valve is in operation after the engine start-

ing process is complete.

Judgment Criteria

• The EGR valve motor coil surge voltage (battery 

positive voltage +2 volts) is not detected for 30 
seconds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-4

.

.

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

• EGR valve (stepper motor) failed.

• Open or shorted EGR valve (stepper motor) cir-

cuit, harness damage, or connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

START

END

MALFUNCTION

GOOD

MONITORING

CONDITIONS

WAS SURGE VOLTAGE

(> V

B

+2V) DETECTED?

NO

NO

YES

YES

AK302951