Mitsubishi Galant 9G. Manual — part 760

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-482

STEP 8. Check for open circuit and short circuit to ground
and harness damage between No. 2 cylinder injector
connector B-30 (terminal No. 2) and PCM connector B-23
(terminal No. 146).
Q: Is the harness wire in good condition?

YES : Go to Step 9.
NO : Repair it. Then go to Step 10.

M

1

2

AK303846

B-30 (GR)

CONNECTOR: B-30

HARNESS CONNECTOR:
COMPONENT SIDE

AB

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-483

STEP 9. Using the oscilloscope, check the No. 2 cylinder
injector.
(1) Disconnect the No. 2 cylinder injector connector B-30 and

connect the test harness special tool MB991658 between
the separated connectors. (All terminals should be
connected.)

(2) Connect the oscilloscope probe to the injector side

connector terminal No. 2.
NOTE: When measuring with the PCM side connector, dis-
connect the all PCM connectors and connect check har-
ness special tool (MB991923) between the separated
connectors. Then connect the oscilloscope probe to the
check harness connector terminal No. 146.

(3) Start the engine and run at idle.

(4) Measure the waveform.

• The waveform should show a normal pattern similar to

the illustration.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the waveform normal?

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

.

NO : Replace the PCM. Then go to Step 10.

STEP 10. 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

P.13A-6

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0202 set?

YES : Retry the troubleshooting.
NO : The inspection is complete.

M

1

2

AK303846

B-30 (GR)

CONNECTOR: B-30

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK302166

1 2

INJECTOR
CONNECTOR

MB991658

OSCILLOSCOPE

AB

AKX01557 AB

A

NORMAL WAVEFORM

A:INJECTOR DRIVE TIME

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-484

DTC P0203: Injector Circuit-Cylinder 3

CAUTION

If DTC P0203 has been set, TCL related DTC
U1120 is also set. After P0203 has been diag-
nosed, don't forget to erase DTC U1120.

2

1

1

2

3

4

AK400886

121 122 123 124 125 126 127

128 129 130 131 132 133

134 135 136 137 138 139 140

141 142 143 144 145 146

147 148 149 150 151 152 153

RED

GREEN-ORANGE

B-17X

MFI
RELAY

INJECTOR
NO. 3

B-03

(MU802062)

4

1

2

3

POWERTRAIN CONTROL
MODULE (PCM)

140

B-23

Injector Circuit-Cylinder 3

RED-

WHITE

RED-

WHITE

BATTERY

1

2

TO PCM

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-485

.

CIRCUIT OPERATION

• The injector power is supplied from the MFI relay

(terminal No. 4).

• The PCM controls the injector by turning the

power transistor in the PCM "ON" and "OFF".

.

TECHNICAL DESCRIPTION

• The amount of fuel injected by the injector is con-

trolled by the amount of continuity time the coil is
grounded by the PCM.

• A surge voltage is generated when the injectors

are driven and the current flowing to the injector
coil is shut off.

• The PCM checks this surge voltage.

.

DESCRIPTIONS OF MONITOR METHODS

Off-surge does not occur after injector is operated.

.

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)

• Not applicable

.

AK303848

B-03 (GR)

CONNECTOR: B-03

AB

AK303803AB

CONNECTOR: B-17X

MFI RELAY

B-17X

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23