Mitsubishi Galant 9G. Manual — part 1120

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-780

(5) Set scan tool MB991958 to the data reading mode.

• Item 73, Fuel Tank Differential Pressure Sensor.

• The fuel tank pressure reading on the scan tool

should be

−1.5 to 1.5 kPa (−0.443 to 0.443 inHg).

(6) Connect the evaporative emission system pressure pump

(Miller number 6872A) to the fuel tank filler tube by using
fuel tank adapter (MLR-8382) and pressurize the fuel tank.

• The fuel tank pressure reading should increase.

(7) Turn the ignition switch to the "LOCK" (OFF) position. Then

disconnect scan tool MB991958.

(8) Remove the evaporative emission system pressure pump

(Miller number 6872A) and the fuel tank adapter
(MLR-8382), and reinstall the fuel cap.

(9) Connect hose H to the evaporative emission canister.
Q: Is the fuel tank pressure between

−1.5 and 1.5 kPa

(

−0.443 and 0.443 inHg)?

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

P.00-14

). Go to

Step 17.

NO : Go to Step 2.

AC306661

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-781

STEP 2. Measure the sensor output voltage at PCM
connector B-20 by using check harness special tool
MB991923.
(1) Disconnect all the connectors from the PCM.

(2) Connect special tool MB991923 (check harness) between

the PCM and the body-side harness connector.

(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.

AC306248

B-20 HARNESS

CONNECTOR:

COMPONENT SIDE

AB

B-20

CONNECTOR: B-20

PCM

AIR
CLEANER

AC209793AJ

SPECIAL TOOL 23-PIN CONNECTOR
WITHOUT RED TAPE
(PCM CONNECTOR B-20)

B-20

PCM

MB991923

BODY SIDE
HARNESS

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-782

(5) Measure the voltage between terminal 23 and ground.

• The voltage should measure between 2.0 and 3.0 volts.

(6) Install the fuel cap.
(7) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 2.0 and 3.0 volts?

YES : Go to Step 16.
NO : Go to Step 3.

STEP 3. Measure the 5-volt reference signal at PCM
connector B-20 by using check harness special tool
MB991923.
(1) Disconnect all the connectors from the PCM.

AC211194 AB

SPECIAL TOOL 23-PIN
CONNECTOR
(WITHOUT RED TAPE):
COMPONENT SIDE

AC306248

B-20 HARNESS

CONNECTOR:

COMPONENT SIDE

AB

B-20

CONNECTOR: B-20

PCM

AIR
CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-783

(2) Connect special tool MB991923 (check harness) between

the PCM and the body-side harness connector.

(3) Turn the ignition switch to the "ON" position.

(4) Measure the voltage between terminal 21 and ground.

• The voltage should measure between 4.9 and 5.1 volts.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?

YES : Go to Step 5.
NO : Go to Step 4.

AC209793AJ

SPECIAL TOOL 23-PIN CONNECTOR
WITHOUT RED TAPE
(PCM CONNECTOR B-20)

B-20

PCM

MB991923

BODY SIDE
HARNESS

AC211192AB

SPECIAL TOOL 23-PIN
CONNECTOR
(WITHOUT RED TAPE):
COMPONENT SIDE