Mitsubishi Montero (2004+). Manual — part 167

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-155

TECHNICAL DESCRIPTION

• The engine coolant temperature sensor converts

the engine coolant temperature to a voltage and
outputs it.

• The PCM checks whether this voltage is within a

specified range.

.

DESCRIPTIONS OF MONITOR METHODS

• Engine coolant temperature sensor output volt-

age drops from over 40

°C (104°F) to under 40°C

(104

°F) and keeps under 40°C (104°F) for 5 min-

utes.

• Engine coolant temperature sensor output volt-

age does not reach close loop enable tempera-
ture within specified period when engine coolant
temperature sensor output voltage at engine start
is under 7

°C (45°F).

.

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)

• Not applicable

Sensor (The sensor below is determined to be

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-156

DTC SET CONDITIONS <Range/Performance problem

− low input>

Logic Flow Chart

Check Conditions, Judgement Criteria

• Engine coolant temperature decreases from

higher than 40

°C (104°F) to lower than 40°C

(104

°F).

• Then the engine coolant temperature has contin-

ued to be 40

°C (104°F) or lower for 5 minutes.

.

START

END

YES

NO

NO

YES

MALFUNCTION

GOOD

TIME HAVE PASSED

AFTER STARTING?*

ENGINE
COOLANT
TEMP.

TEMP. WHERE
CLOSED LOOP
STARTS

>

MONITORING

CONDITIONS?

NO

YES

*: SEE DTC SET CONDITIONS-SET CONDITIONS, JUDGMENT CRITERIA

AK302927

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-157

DTC SET CONDITIONS <Range/Performance problem

− drift>

Logic Flow Chart

Check Conditions, Judgement Criteria

• About 60 − 300 seconds have passed for the

engine coolant temperature to rise to about 7

°C

(44.6

°F) after starting sequence was completed.

• However, time is not counted when fuel is shut

off.

.

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: )

• Engine coolant temperature sensor failed.

• Harness damage or connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

START

END

NO

NO

YES

YES

MALFUNCTION

GOOD

UNDER 40˚C (107˚F)

300secs HAVE PASSED?

NO

YES

OVER 40˚C (107˚F)

YES

OVER 40˚C (107˚F)

NO

AK302928

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-158

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, check data list item 21:
Engine Coolant Temperature Sensor.

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 data reading mode for item

21, Engine Coolant Temperature Sensor.

• The engine coolant temperature and temperature

shown with the scan tool should approximately match.

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

YES : It can be assumed 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