Mitsubishi Galant (2004+). Manual — part 1232
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>
13B-621
STEP 20. 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
(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0340 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.
DTC P0401: Exhaust Gas Recirculation Flow Insufficient Detected
.
TECHNICAL DESCRIPTION
• When the EGR valve (stepper motor) is actuated
from the fully closed position toward the open
position while the engine is running, EGR gas
flows.
• The PCM checks how the EGR gas flow signal
changes.
.
DESCRIPTIONS OF MONITOR METHODS
Small manifold pressure change during exhaust gas
recirculation (EGR) operation from closed to
open.
.
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)
• EGR stepper motor 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
• Manifold absolute pressure sensor
• Accelerator pedal position sensor
.
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>
13B-622
DTC SET CONDITIONS
Logic Flow Chart
.
Check Conditions
• At least 14 seconds have passed since the last
monitor was complete.
• Engine coolant temperature is higher than 76°C
(169
°F).
• Engine speed is at between 970 and 1,650 r/min.
• Intake air temperature is higher than −10°C
(14
°F).
• Barometric pressure is higher than 76 kPa (22.4
in.Hg).
• Vehicle speed is 30 km/h (19 mph) or more.
• At least 90 seconds have passed since manifold
absolute pressure sensor output voltage fluctu-
ated 1.5 volts or more.
• Battery positive voltage is higher than 10.3 volts.
• The throttle valve is closed.
• Volumetric efficiency is lower than 29 percent.
• The PCM monitors for this condition for 3 cycles
of 1.8 seconds each during the drive cycle.
START
END
NO
NO
NO
YES
YES
YES
MALFUNCTION
GOOD
MONITORING
CONDITIONS
MEASURE MANIFOLD
PRESSURE (P1)
MEASURE MANIFOLD
PRESSURE (P2)
EGR VALVE OPEN
P2 - P1 < P0 *
SPECIFIED TIMES
AK204016
P0 : THRESHOLD VALUE
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>
13B-623
Judgement Criteria
• When the EGR valve opens to the prescribed
opening, when intake manifold pressure fluctua-
tion width is lower than 2.0 kPa (0.59 in.Hg).
.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function
− OBD-II Drive Cycle −
Procedure 5
− Exhaust Gas Recirculation (EGR)
System Monitor
.
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are: )
• Contaminated EGR valve and EGR passage.
• EGR valve (stopper motor) failed.
• Open or shorted EGR valve (stopper motor) cir-
cuit, or connector damage.
• Manifold absolute pressure sensor failed.
• 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 the EGR system
Refer to GROUP 17, Emission Control System
− Exhaust Gas
Recirculation (EGR) System
− General Information
Q: Are there any abnormalities?
YES : Repair it. Then go to Step 3.
NO : Go to Step 2.
STEP 2. Using scan tool MB991958, check data list item 95:
Manifold Absolute Pressure 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
95, Manifold Absolute Pressure Sensor.
(4) Warm up the engine to normal operating temperature: 80
°C
to 95
°C (176°F to 203°F).
• Should be between 16 − 36 kPa (4.7 − 10.6 in.Hg) at
engine idling.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Clean the EGR valve and EGR passage. Then go to
Step 3.
NO : Refer to DTC P0106
− Manifold Absolute Pressure
Sensor Circuit Range/Performance Problem
− Manifold Absolute Pressure
Sensor Circuit Low Input
, DTC P0108
−
Manifold Absolute Pressure Sensor Circuit High Input
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>
13B-624
STEP 3. 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 5 −
Exhaust Gas Recirculation (EGR) System Monitor
.
(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0401 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.
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