Mitsubishi Galant (2004+). Manual — part 1202

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-501

STEP 10. Check for open circuit and short circuit to
ground and harness damage between intermediate
connector B-32 (terminal No. 10) and PCM connector B-23
(terminal No. 140).

Q: Is the harness wire in good condition?

YES : Go to Step 11.
NO : Repair it. Then go to Step 12.

AK303053

3

4

5

8

9

1

2

6

7

10

CONNECTOR: B-32

HARNESS CONNECTOR:
COMPONENT SIDE

AB

B-32 (B)

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) <3.8L ENGINE>

13B-502

STEP 11. Using the oscilloscope, check the No. 3 cylinder
injector.

(1) Disconnect the intermediate connector B-32 and connect

the test harness MB991658 between the separated
connectors.

(2) Connect the oscilloscope probe to injector intermediate

connector terminal No. 10.
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 an oscilloscope to probe to termi-
nal No. 140.

(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 00E, How to Use Troubleshooting/Inspection
Service Points

P.00-6

.

NO : Replace the PCM. Then go to Step 12.

STEP 12. 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.13B-5

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0203 set?

YES : Repeat the troubleshooting.
NO : The procedure is complete.

AK303053

3

4

5

8

9

1

2

6

7

10

CONNECTOR: B-32

HARNESS CONNECTOR:
COMPONENT SIDE

AB

B-32 (B)

1

2 3

6

7 8

4 5

9 10

AK203300

OSCILLOSCOPE

MB991658

B-32 INTERMEDIATE
CONNECTOR

AB

AKX01557 AB

A

NORMAL WAVEFORM

A:INJECTOR DRIVE TIME

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-503

DTC P0204: Injector Circuit Malfunction - Cylinder 4

CAUTION

If DTC P0204 has been set, TCL related DTC
U1120 is also set. After P0204 has been diag-
nosed, don't forget to erase DTC U1120.

AK302852

RED-

WHITE

GRA

Y

-BLA

CK

RED

RED-

WHITE

RED-

WHITE

139

B-17X

POWERTRAIN CONTROL
MODULE (PCM)

1

2

INJECTOR
NO. 4

B-27

MFI
RELAY

BATTERY

4

3

1

2

B-23

2

1

Injector Circuit - Cylinder 4

3 4

1 2

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-504

.

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

.

AK303109

CONNECTOR: B-27

B-27 (GR)

AB

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23