Mitsubishi Galant 9G. Manual — part 1089

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-656

STEP 9. Check the EGR valve operation using special tool
MB991658.
(1) Remove the EGR valve.

(2) Connect special tool MB991658 to the EGR valve. (All

terminals should be connected.)

(3) Use the jumper wires to connect terminal No. 5 of the EGR

valve onnector to the positive battery terminal.

(4) Check to ensure that the motor operates when the terminal

No. 1 and No. 3 of the EGR valve connector are
respectively connected to the negative battery terminal
using a jumper wire.

• Vibration should be present at each application of volt-

age to test clip combination.

(5) Then, use jumper wires to connect the terminal No. 2 of the

EGR valve connector to the positive battery terminal.

(6) Check to ensure that the motor operates when terminal No.

4 and No. 6 of the EGR valve connector are respectively
connected to the negative battery terminal using a jumper
wire.

• Vibration should be present at each application of volt-

age to test clip combination.

(7) Reinstall the EGR valve, using a new gasket, and tighten to

the specified torque.

Tighten torque : 24

± 3 N⋅m [17 ± 3 ft⋅Ib]

Q: Is the EGR valve operating properly?

YES : Go to Step 10.
NO : Replace the EGR valve. Then go to Step 12.

1

2 3

4

5 6

AK303137AB

B-105(GR)

CONNECTOR: B-105

EGR
VALVE

BRAKE FLUID
RESERVOIR

HARNESS
CONNECTOR:
COMPONENT SIDE

AK203699

+

-

AB

BATTERY

MB991658

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-657

STEP 10. Check for harness damage between MFI relay
connector B-17X (terminal No. 4) and EGR valve connector
B-105 (terminal No. 2, No. 5).
Q: Is the harness wire in good condition?

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

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

1

2 3

4

5 6

AK303137AB

B-105(GR)

CONNECTOR: B-105

EGR
VALVE

BRAKE FLUID
RESERVOIR

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-658

STEP 11. Check for harness damage between EGR valve
connector B-07 and PCM connector B-23.

a. EGR valve connector B-105 (terminal No. 1) and PCM con-

nector B-23 (terminal No. 142).

b. EGR valve connector B-105 (terminal No. 3) and PCM con-

nector B-23 (terminal No. 136).

c. EGR valve connector B-105 (terminal No. 4) and PCM con-

nector B-23 (terminal No. 130).

d. EGR valver connector B-105 (terminal No. 6) and PCM con-

nector B-23 (terminal No. 124).

Q: Is the harness wire in good condition?

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.13B-6

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0403 set?

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

1

2 3

4

5 6

AK303137AB

B-105(GR)

CONNECTOR: B-105

EGR
VALVE

BRAKE FLUID
RESERVOIR

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

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-659

DTC P0421: Warm Up Catalyst Efficiency Below Threshold (bank 1)

.

TECHNICAL DESCRIPTION

• The signal from the rear heated oxygen sensor

differs from the front heated oxygen sensor. That
is because the catalytic converter purifies
exhaust gas. When the catalytic converter has
deteriorated, the signal from the front heated oxy-
gen sensor becomes similar to the rear heated
oxygen sensor.

• The PCM compares the output of the front and

rear heated oxygen sensor signals.

.

DESCRIPTIONS OF MONITOR METHODS

Front and rear heated oxygen sensor rich/lean

switching frequencies are nearly equal.

.

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)

• Heated oxygen sensor (front) monitor

• Heated oxygen sensor (rear) monitor

• Heated oxygen sensor heater (front) monitor

• Heated oxygen sensor heater (rear) monitor

• Misfire monitor

• Fuel system monitor

• Air/fuel ratio feedback monitor

• Oxygen sensor heater (front)

• Oxygen sensor heater (rear)

Sensor (The sensor below is determined to be

normal)

• Mass airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

• Accelerator pedal position sensor

.