Mitsubishi Montero (2004+). Manual - part 292

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-655

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Vehicle speed has reached 1.5 km/h (1 mph) or 

more at least once.

• Under the closed loop idle speed control.

• Engine coolant temperature is higher than 77°C 

(171

°F).

• Battery positive voltage is higher than 10 volts.

• Barometric pressure is higher than 76 kPa (22.4 

in.Hg).

• Intake air temperature is higher than −10°C 

(14

°F).

• 60 seconds have elapsed from the start of the 

previous monitoring.

• Target throttle actuator control motor position is 0 

steps.

Judgment Criteria

• Actual idle speed has continued to be higher than 

the target idle speed by 200 r/min (300 r/min*) or 
more for 12 seconds.
*: Specs in parentheses are applicable if the max-

imum air temperature during the previous 
operation was more than 45

°C (113°F).

.

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: )

• Intake system vacuum leak.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

START

CALCULATE  

Ne

MONITORING

CONDITIONS

Ne = (ACTUAL-Ne) - (TARGET-Ne)

Ne: ENGINE SPEED

  

Ne < -100 r/min OR

> 200 r/min

HAVE 10secs PASSED?

AK302956

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-656

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

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, read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P0507 set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-26

.

NO :  Go to Step 2.

STEP 2. Check the intake system vacuum leak.
Q: Are there any abnormalities?

YES : Repair or replace it. Then go to Step 4.
NO :  Go to Step 3.

STEP 3. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor 

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0507 set?

YES : Replace the PCM. Then go to Step 4.
NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspectuin Service Points 

P.00-6

.

STEP 4. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor 

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0507 set?

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

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-657

DTC P0551: Power Steering Pressure Sensor Circuit Range/Performance

.

CIRCUIT OPERATION

• A battery positive voltage is applied to the power 

steering pressure switch output terminal (terminal 
No. 1) from the PCM (terminal No. 47) via the 
resistor in the PCM.

.

TECHNICAL DESCRIPTION

• The power steering pressure switch converts the 

existence of a power steering load into a high/low 
voltage, and inputs it into the PCM.

• When the steering wheel is turned, hydraulic 

pressure rises. The power steering pressure 
switch closes, and the applied battery positive 
voltage will be grounded. With this, the power 
steering pressure switch output voltage will fluc-
tuate between 12 volts and 0 volt.

• While driving with the steering wheel held 

straight, the power steering pressure switch turns 
"OFF".

• The PCM checks whether the power steering 

pressure switch turns "OFF" or "ON" during driv-
ing.

.

DESCRIPTIONS OF MONITOR METHODS
Power steering pressure switch stays on during 

specified go/stop operations.

.

MONITOR EXECUTION
Continuous

.

AK201149

YELL

OW

POWERTRAIN
CONTROL
MODULE (PCM)

1

B-29

(MU801211)

POWER STEERING
PRESSURE SWITCH

47

1

Power Steering Pressure Switch Circuit

31

35363738394041 42 43
444546474849

50 51

5253

545556

57 58

32

33 34

D-133

(MU803803)

AK200972

POWER 
STEERING 
OIL PUMP

POWER STEERING 
PRESSURE SWITCH

AB

B-29(B)

CONNECTOR: B-29

AK201038

CONNECTOR: D-133

AC

PCM

D-133(GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-658

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Engine coolant temperature sensor

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions 

• Engine coolant temperature is higher than 30°C 

(86

°F). 

• Drive for 4 seconds or more with the vehicle 

speed is 50 km/h (31 mph) or more. Stop the 
vehicle [vehicle speed is 1.5 km/h (1 mph) or 
less]. Repeat 10 times or more. 

Judgment Criteria 

• Power steering pressure switch continues to be 

"ON". 

.

OBD-II DRIVE CYCLE PATTERN
None.

.

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

• Power steering pressure switch failed. 

YES

NO

NO

NO

MONITORING

CONDITIONS

END

MALFUNCTION

GOOD

START

POWER STEERING

SWITCH = "ON"

YES

GO/STOP OPERATION

FOR SPECIFIED TIMES

YES

AK302957