Mitsubishi Galant (2004+). Manual - part 1094

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-69

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CIRCUIT OPERATION

• A 5-volt voltage is supplied to the manifold abso-

lute pressure sensor power terminal (terminal No. 
3) from the PCM (terminal No. 68). The ground 
terminal (terminal No. 2) is grounded with PCM 
(terminal No. 69).

• A voltage that is proportional to the intake mani-

fold pressure is sent to the PCM (terminal No. 
102) from the manifold absolute pressure sensor 
output terminal (terminal No. 1).

.

TECHNICAL DESCRIPTION

• The manifold absolute pressure sensor outputs a 

voltage which corresponds to the intake manifold 
pressure.

• The PCM checks whether this voltage is within a 

specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Compare load value with manifold absolute pressure 

sensor output voltage.

.

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)

• Engine coolant temperature sensor

• Throttle position sensor

.

AK303022

CONNECTOR: B-02

AB

MANIFOLD
ABSOLUTE
PRESSURE
SENSOR

INTAKE
MANIFOLD

B-02 (B)

AK303013

CONNECTORS: B-21, B-22

PCM

AB

AIR CLEANER

B-22 (B)

B-21 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-70

DTC SET CONDITIONS <Range/Performance problem - low input>

Logic Flow Chart

.

Check Conditions

• 8 minutes or more have passed since the starting 

sequence was completed, when the engine cool-
ant temperature at engine start is 0

°C (32°F) or 

lower.

• Engine speed is higher than 1,500 r/min.

• Throttle position sensor output voltage is higher 

than 3.5 volts.

Judgement Criteria

• Manifold Absolute pressure is 45 kPa (8.3 in.Hg) 

or lower for 2 seconds.

.

START

YES

YES

YES

YES

NO

NO

NO

NO

MONITORING

CONDITIONS

PRESSURE < 

45kPa (8.3in.Hg)

CONTINUOUS

FAILURE FOR 2secs

MALFUNCTION

END

GOOD

THROTTLE POSITION > =3.5V

AK302381

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-71

DTC SET CONDITIONS <Range/Performance problem - high input>

Logic Flow Chart

.

Check Conditions

• 8 minutes or more have passed since the starting 

sequence was completed, when the engine cool-
ant temperature at engine start is 0

°C (32°F) or 

lower.

• Engine speed is lower than 1,500 r/min.

• Throttle position sensor output voltage is lower 

than 0.9 volt.

Judgement Criteria

• Manifold Absolute pressure is 89 kPa (26.3 

in.Hg) or higher for 2 seconds.

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OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-5

.

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TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are: )

• Manifold absolute pressure sensor failed.

• Open or shorted manifold absolute pressure sen-

sor circuit, harness damage or connector dam-
age.

• PCM failed.

START

YES

YES

YES

YES

NO

NO

NO

NO

MONITORING

CONDITIONS

PRESSURE > 89kPa (26.3in.Hg)

CONTINUOUS

FAILURE FOR 2secs

MALFUNCTION

END

GOOD

THROTTLE POSITION < =0.9V

AK302380

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-72

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991923: Power Plant ECU Check Harness

STEP 1. 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) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode for item 

95, Manifold Absolute Pressure Sensor.

• When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg).

• When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg).

• When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 

in.Hg).

• When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 

in.Hg).

(4) Start the engine.

• When the engine is idling, 16 − 36 kPa (4.7 − 10.6 

in.Hg).

• When the engine is suddenly revved, manifold absolute 

pressure varies.

(5) 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.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827