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?

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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.

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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