Mitsubishi Galant 9G. Manual — part 673
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-134
.
CIRCUIT OPERATION
• 5-volt voltage is applied to the engine coolant
temperature sensor output terminal (terminal No.
1) from the PCM (terminal No. 93) via the resistor
in the PCM. The ground terminal (terminal No. 2)
is grounded with PCM (terminal No. 69).
• The engine coolant temperature sensor is a neg-
ative temperature coefficient type of resistor. It
has the characteristic that when the engine cool-
ant temperature rises the resistance decreases.
• The engine coolant temperature sensor output
voltage increases when the resistance increases
and decreases when the resistance decreases.
.
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 voltage
does not change for specified period when
engine coolant temperature sensor output volt-
age at engine start is over 7
°C (45°F).
.
MONITOR EXECUTION
Once per driving cycle
.
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)
• Mass airflow sensor
• Engine coolant temperature sensor
• Intake air temperature sensor
.
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-135
DTC SET CONDITIONS
Logic Flow Chart
.
Check Conditions
• Engine coolant temperature was 7°C (45°F) or
more when the engine started.
Judgement Criteria
• Engine coolant temperature fluctuates within 1°C
(34
°F) after 5 minutes have passed since the
engine was started.
• However, time is not counted if any of the follow-
ing conditions are met.
1. Intake air temperature is 60
°C (140°F) or
more.
2. Mass airflow sensor output is 10 g/sec or less.
3. During fuel shut-off operation.
.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function
−OBD-II Drive
Cycle
.
.
START
END
YES
NO
NO
YES
MALFUNCTION
GOOD
300secs HAVE PASSED?
|dT| < 1˚C(34˚F)
MONITORING CONDITIONS?
START MEASURING THE MINIMUM AND MAXIMUM
TEMPERATURE FROM ENGINE START
CALCULATE THE DIFFERENCE OF THE MINIMUM AND
THE MAXIMUM TEMPERATURE FROM ENGINE START;dT
YES
NO
AK401491
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-136
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.
• MB991827: USB Cable
• MB991910: Main Harness A
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
− How to
Cope with Intermittent Malfunctions
.
NO : Go to Step 2.
AK303804AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-137
STEP 2. Check the engine coolant temperature sensor.
(1) Disconnect the engine coolant temperature sensor
connector B-104.
(2) Remove the engine coolant temperature sensor.
(3) With the temperature sensing portion of engine coolant
temperature sensor immersed in hot water, measure
resistance.
Standard value:
14
− 17 kΩ [at −20°C (−4°F)]
5.1
− 6.5 kΩ [at 0°C (32°F)]
2.1
− 2.7 kΩ [at 20°C (68°F)]
0.9
− 1.3 kΩ [at 40°C (104°F)]
0.48
− 0.68 kΩ [at 60°C (140°F)]
0.26
− 0.36 kΩ [at 80°C (176°F)]
(4) Apply 3M
AAD part number 8731 or equivalent on the
screw section of the engine coolant temperature sensor.
(5) Install the engine coolant temperature sensor, and tighten
to the specified torque.
Tightening torque: 30
± 9 N⋅m (22 ± 7 ft-lb)
Q: Is the measured resistance at the standard value?
YES : Go to Step 3.
NO : Replace the engine coolant temperature sensor. Then
go to Step 9.
STEP 3. Check harness connector B-104 at the engine
coolant temperature sensor for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness
. Then go to Step 9.
AK303815
1
2
AB
CONNECTOR: B-104
B-104 (B)
HARNESS
CONNECTOR:
COMPONENT SIDE
AKX01622
AKX01623 AB
AK303815
1
2
AB
CONNECTOR: B-104
B-104 (B)
HARNESS
CONNECTOR:
COMPONENT SIDE
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