Mitsubishi Galant (2004+). Manual — part 1136

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-237

.

CIRCUIT OPERATION

• Power is supplied from the MFI relay (terminal

No. 4) to the right bank heated oxygen sensor
(front) heater.

• The PCM (terminal No. 126) controls continuity to

the right bank 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
Right bank heated oxygen sensor heater (front) cur-

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

°C (68°F).

.

MONITOR EXECUTION
Continuous

.

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

AK303047

B-09 (B)

CONNECTOR: B-09

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-238

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

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 60 seconds have elapsed from the start of the

previous monitoring.

• Engine coolant temperature is higher than 20°C

(68

°F).

• While the right bank heated oxygen sensor (front)

heater is on.

• Battery positive voltage is between 11 and 16.5

volts.

Judgment Criteria

• The right bank heated oxygen sensor (front)

heater current has continued to be lower than
0.16 ampere or higher than 7.5 ampere for 4 sec-
onds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function

− OBD-II Drive Cycle −

Procedure 6

− Other Monitor

P.13B-5

.

.

START

END

YES

YES

YES

YES

NO

NO

NO

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 4secs

MONITORING

CONDITIONS

CURRENT < 0.16A

CURRENT > 7.5A

AK302400

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-239

TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are: )

• Open or shorted right bank heated oxygen sen-

sor (front) heater circuit, harness damage, or
connector damage.

• Open circuit in right bank heated oxygen sensor

(front) heater.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MD998464: Test Harness

• MB991923: Power Plant ECU Check Harness

STEP 1. Check harness connector B-09 at the right bank
heated oxygen sensor (front) for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 12.

1

2

3

4

AK303048

B-09 (B)

CONNECTOR: B-09

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-240

STEP 2. Check the right bank heated oxygen sensor
(front).

(1) Disconnect right bank heated oxygen sensor (front)

connector B-09 and connect test harness special tool,
MD998464, to the connector on the right bank heated
oxygen (front) sensor side.

(2) Measure the resistance between heated oxygen sensor

connector terminal No. 1 (red clip) and terminal No. 3 (blue
clip).

Standard value: 4.5

− 8.0 ohms [at 20°C (68°F)]

Q: Is the measured resistance between 4.5 and 8.0 ohms

[at 20

°C (68°F)]?

YES : Go to Step 3.
NO : Replace the right bank heated oxygen sensor (front).

Then go to Step 12.

1

2

3

4

AK303048

B-09 (B)

CONNECTOR: B-09

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

MD998464

BLUE

RED

AC