Mitsubishi Galant (2004+). Manual — part 900
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-417
STEP 6. Check the cylinder 1, 4 injector.
(1) Disconnect the cylinder 1, 4 injector connector B-01, B-27.
(2) Measure the resistance between each injector side
connector terminal No. 1 and No. 2.
Standard value: 10.5
− 13.5 ohms [at 20°C (68°F)]
Q: Is the measured resistance between 10.5 and 13.5 ohms
[at 20
°C (68°F)]?
YES : Go to Step 7.
NO : Replace the injector. Then go to Step 9.
STEP 7. Check the fuel pressure.
Refer to On-vehicle Service
− Fuel Pressure Test
Q: Is the fuel pressure normal?
YES : Repair it. Then go to Step 9.
NO : Go to Step 8.
STEP 8. Replace the cylinder 1, 4 injector.
(1) Replace the cylinder 1, 4 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 the diagnostic trouble code (DTC).
Q: Is DTC P0172 set?
YES : Replace the PCM. Then go to Step 9.
NO : The inspection is complete.
STEP 9. 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 DTC P0172 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.
M
1
2
AK303822
B-01 (GR)
B-27 (GR)
CONNECTORS: B-01, B-27
AB
HARNESS CONNECTOR:
COMPONENT SIDE
AK000559
2
1
INJECTOR SIDE
CONNECTOR
AB
M
1
2
AK303822
B-01 (GR)
B-27 (GR)
CONNECTORS: B-01, B-27
AB
HARNESS CONNECTOR:
COMPONENT SIDE
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-418
DTC P0174: System too Lean (cylinder 2, 3)
CAUTION
If DTC P0174 has been set, TCL related DTC
U1120 is also set. After P0174 has been diag-
nosed, don't forget to erase DTC U1120.
.
Fuel Trim Circuit
• Refer to DTC P0202 − Injector Circuit-cylinder 2
− Injector Circuit-cylinder
3
.
CIRCUIT OPERATION
• Refer to DTC P0202 − Injector Circuit-cylinder 2
− Injector Circuit-cylinder
3
.
TECHNICAL DESCRIPTION
• If a malfunction occurs in the fuel system, the fuel
trim value becomes too large.
• The PCM checks whether the fuel trim value is
within a specified range.
.
DESCRIPTIONS OF MONITOR METHODS
Cylinder 2, 3 air/fuel learning value (long time fuel
trim) and air/fuel feedback integral value (short
time fuel trim) are too lean.
.
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)
• Mass airflow sensor
• Engine coolant temperature sensor
• Intake air temperature sensor
• Barometric pressure sensor
• Throttle position sensor
.
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-419
DTC SET CONDITIONS
Logic Flow Chart
.
Check Conditions
• Engine coolant temperature is lower than 100°C
(212
°F) when the engine is started.
• Intake air temperature is lower than 60°C (140°F)
when the engine is started.
• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 77°C
(171
°F).
• Mass airflow sensor output is 6 g/sec or more.
Judgment Criteria
• Long-term fuel trim has continued to be higher
than +12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be higher
than +10.0 percent for 5 seconds. <Federal>
or
• Short-term fuel trim has continued to be higher
than +7.0 percent for 5 seconds. <California>
Check Conditions
• Engine coolant temperature is lower than 100°C
(212
°F) when the engine is started.
• Intake air temperature is lower than 60°C (140°F)
when the engine is started.
• Under the closed loop air/fuel ratio control.
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
AK204050
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-420
• Engine coolant temperature is higher than 77°C
(171
°F).
• Mass airflow sensor output is 6 g/sec or less.
Judgment Criteria
• Long-term fuel trim has continued to be higher
than +12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be higher
than +15.0 percent for 5 seconds.
Check Conditions
• Engine coolant temperature is higher than 100°C
(212
°F) when the engine is started.
• Intake air temperature is higher than 60°C
(140
°F) when the engine is started.
• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 77°C
(171
°F).
• Mass airflow sensor output is 6 g/sec or more.
Judgment Criteria
• Long-term fuel trim has continued to be higher
than +12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be higher
than +20.0 percent for 5 seconds.
Check Conditions
• Engine coolant temperature is higher than 100°C
(212
°F) when the engine is started.
• Intake air temperature is higher than 60°C
(140
°F) when the engine is started.
• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 77°C
(171
°F).
• Mass airflow sensor output is 6 g/sec or less.
Judgment Criteria
• Long-term fuel trim has continued to be higher
than +12.5 percent for 5 seconds.
or
• Short-term fuel trim has continued to be higher
than +25.0 percent for 5 seconds.
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 +25.0
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:)
• Mass airflow sensor failed.
• Injector (Number 2, 3) failed.
• Incorrect fuel pressure.
• Air drawn in from gaps in gasket, seals, etc.
• Engine coolant temperature sensor failed.
• Intake air temperature sensor failed.
• Barometric pressure sensor failed.
• Manifold absolute pressure sensor failed.
• Exhaust leak.
• Use of incorrect or contaminated fuel.
• Harness damage in cylinder 2, 3 injector circuit or
connector damage.
• PCM failed.
DIAGNOSIS
Required Special Tools:
• MB991958: Scan Tool (MUT-III Sub Assembly)
• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A
STEP 1. Check for exhaust leak.
Q: Are there any abnormalities?
YES : Repair it. Then go to Step 15.
NO : Go to Step 2.
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