Mitsubishi Galant 9G. Manual - part 725

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-342

STEP 9. Check for harness damage between cylinder 2, 3
heated oxygen sensor (front) connector B-36 (terminal No.
4) and PCM connector B-22 (terminal No. 91).
Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO : Repair it. Then go to Step 12.

AK303830

CONNECTOR: B-36

B-36 (GR)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (FRONT)

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303016

104

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-343

STEP 10. Check for harness damage between cylinder 2, 3
injector connector and PCM connector.

a. Check the harness wire between injector connector B-30

(terminal No. 2) and PCM connector B-23 (terminal No.
146) at No. 2 cylinder.

b. Check the harness wire between injector connector B-03

(terminal No. 2) and PCM connector B-23 (terminal No.
140) at No. 3 cylinder.

Q: Is the harness wire in good condition?

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

STEP 11. Check the fuel pressure.
Refer to On-vehicle Service

− Fuel Pressure Test

P.13A-1124

Q: Is the fuel pressure normal?

YES : Replace the PCM. Then go to Step 12.
NO : Repair it. 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.13A-6

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0154 set?

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

AK303831

B-30 (GR) B-03 (GR)

CONNECTORS: B-03, B-30

HARNESS CONNECTOR:
COMPONENT SIDE

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

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-344

DTC P0155: Cylinder 2, 3 Heated Oxygen Sensor Heater Circuit (sensor 1)

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

AK400881

RED-

WHITE

RED

CYLINDER 2, 3 HEATED

OXYGEN SENSOR (FRONT)

B-17X

BATTERY

125

MFI
RELAY

B-36

MU802665

POWERTRAIN
CONTROL
MODULE (PCM)

Cylinder 2, 3 Heated Oxygen Sensor (front) Heater Circuit

B-23

RED-

WHITE

TO PCM

TO PCM TO PCM

AK303803AB

CONNECTOR: B-17X

MFI RELAY

B-17X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-345

CIRCUIT OPERATION

• Power is supplied from the MFI relay (terminal

No. 4) to the cylinder 2, 3 heated oxygen sensor
(front) heater.

• The PCM (terminal No. 125) controls continuity to

the cylinder 2, 3 heated oxygen sensor (front)
heater by turning the power transistor in the PCM
"ON" and "OFF".

TECHNICAL DESCRIPTION

• The PCM checks whether the heater current is

within a specified range when the heater is ener-
gized.

DESCRIPTIONS OF MONITOR METHODS

Cylinder 2, 3 heated oxygen sensor heater (front)

current is out of specified range when engine
coolant temperature is over 20

°C (68°F).

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

AK303829AB

CONNECTOR: B-36

B-36 (GR)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (FRONT)

AK303059

CONNECTOR: B-23

PCM

AIR CLEANER

B-23

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