Mitsubishi Montero (2004+). Manual — part 222
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-375
STEP 14. Check for entry of foreign matter (water,
kerosene, etc.) into fuel.
Q: Are there any abnormalities?
YES : Replace the fuel. Then go to Step 16.
NO : Go to Step 15.
STEP 15. Replace the right bank injector.
(1) Replace the right bank injector.
(2) Carry out a test drive with the drive cycle pattern. Refer to
Diagnostic Function
− OBD-II Drive Cycle − Procedure 2 −
Fuel Trim Monitor
(3) Check in the diagnostic trouble code (DTC).
Q: Is DTC P0171 set?
YES : Replace the PCM. Then go to Step 16.
NO : The inspection is complete.
STEP 16. 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 2 −
Fuel Trim Monitor
(2) Check the diagnostic trouble code (DTC).
Q: Is the DTC P0171 output?
YES : Retry the troubleshooting.
NO : The inspection is complete.
DTC P0172: System too Rich (bank 1)
.
Fuel Trim Circuit
• Refer to DTC P0201 − P0206, Injector Circuit.
.
CIRCUIT OPERATION
• Refer to DTC P0201 − P0206, Injector Circuit.
.
TECHNICAL DESCRIPTION
• If a malfunction occurs in the fuel system, the fuel
trim value becomes too small.
• The PCM checks whether the fuel trim value is
within a specified range.
.
DESCRIPTIONS OF MONITOR METHODS
Right bank air/fuel learning value (long time fuel trim)
and air/fuel feedback integral value (short time
fuel trim) are too rich.
.
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)
• Misfire 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
.
AK200950
1
2
B-03(GR)
B-02(GR)
B-01(GR)
CONNECTORS: B-01, B-02, B-03
AB
HARNESS
CONNECTOR:
COMPONENT SIDE
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-376
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 77°C
(171
°F).
• Volume airflow sensor output frequency is higher
than 100 Hz.
Judgment Criteria
• Long-term fuel trim has continued to be lower
than
−12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be lower
than
−7.4 percent for 5 seconds.
Check Conditions
• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 77°C
(171
°F).
• Volume airflow sensor output frequency is lower
than 100 Hz.
Judgment Criteria
• Long-term fuel trim has continued to be lower
than
−12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be lower
than
−12.5 percent for 5 seconds.
K
LRN
: LONG-TERM TRIM
K
I
: SHORT-TERM TRIM
K0 : MAXIMUM LIMIT OF LONG-TERM TRIM
K1 : MAXIMUM LIMIT OF SHORT-TERM TRIM
K2 : MINIMUM LIMIT OF LONG-TERM TRIM
K3 : MINIMUM LIMIT OF SHORT-TERM TRIM
START
MONITORING
CONDITIONS
END
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
K
LRN
> K0
MALFUNCTION
GOOD
K
LRN
< K2
K
I
< K3
K
I
> K1
CONTINUOUS FAILURE
FOR 5secs
AK302938
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-377
Check Conditions
• Engine coolant temperature is higher than 77°C
(171
°F).
• Under the closed loop air/fuel ratio control.
Judgment Criteria
• Long-term fuel trim has continued to be −12.5
percent for 5 seconds.
or
• Short-term fuel trim has continued to be −30.0
percent for 5 seconds.
.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function
− OBD-II Drive Cycle −
Procedure 2
− Fuel Trim Monitor
.
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are: )
• Volume airflow sensor failed.
• Injector (Number 1, 3, 5) failed.
• Incorrect fuel pressure.
• Engine coolant temperature sensor failed.
• Intake air temperature sensor failed.
• Barometric pressure sensor failed.
• Use of incorrect or contaminated fuel.
• PCM failed.
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 data list item 12:
Volume Airflow 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) Start the engine and run at idle.
(3) Set scan tool MB991958 to the data reading mode for item
12, Volume Airflow Sensor.
(4) Warm up the engine to normal operating temperature: 80
°C
to 95
°C (176°F to 203°F).
• When idling, between 17 and 43 Hz (between 3.5 and
7.5 gm/s).
• When 2,500 r/min, between 64 and 104 Hz (between
13.6 and 19.6 gm/s).
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : YES: Go to Step 2.
NO : Refer to DTC P0101
− Volume Airflow Circuit
Range/Performance Problem
, DTC P0102
− Volume Airflow Circuit Low Input
.
AK302970
AB
MB991911
MB991824
MB991827
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-378
STEP 2. Using scan tool MB991958, check data list item 13:
Intake Air Temperature Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991958 to the data reading mode for item
13, Intake Air Temperature Sensor.
• The intake air temperature and temperature shown with
the scan tool should approximately match.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 3.
NO : Refer to DTC P0111
− Intake Air Temperature Circuit
Range/Performance Problem
, DTC P0112
− Intake Air Temperature Circuit Low Input
, DTC P0113
− Intake Air Temperature
Circuit High Input
.
STEP 3. Using scan tool MB991958, check data list item 21:
Engine Coolant Temperature Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) 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.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 4.
NO : Refer to DTC P0116
− Engine Coolant Temperature
Circuit Range/Performance Problem
, DTC
P0117
− Engine Coolant Temperature Circuit Low
, DTC P0118
− Engine Coolant
Temperature Circuit High Input
AK302970
AB
MB991911
MB991824
MB991827
AK302970
AB
MB991911
MB991824
MB991827
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