Mitsubishi Galant 9G. Manual - part 726

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-346

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 cylinder 2, 3 heated oxygen sensor 

(front) heater is on.

• Battery positive voltage is between 11 and 16.5 

volts.

Judgment Criteria

• The cylinder 2, 3 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.13A-6

.

.

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

• Open or shorted cylinder 2, 3 heated oxygen sen-

sor (front) heater circuit, or harness damage.

• Open circuit in cylinder 2, 3 heated oxygen sen-

sor (front) heater.

• Connector damage.

• PCM failed.

START

END

YES

YES

YES

YES

NO

NO

NO

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 4secs

MONITORING

CONDITIONS

CURRENT

< 0.16A

CURRENT

> 7.5A

AK302023

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-347

DIAGNOSIS

Required Special Tools:

• MB991316: Test Harness

• MB991923: Check Harness

STEP 1. Check harness connector B-36 at the cylinder 2, 3 
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.

AK303830

1

2

3

4

AB

CONNECTOR: B-36 

B-36 (GR)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (FRONT)

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-348

STEP 2. Check the cylinder 2, 3 heated oxygen sensor 
(front).
(1) Disconnect cylinder 2, 3 heated oxygen sensor (front) 

connector B-36 and connect test harness special tool, 
MB991316, to the connector on the cylinder 2, 3 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 cylinder 2, 3 heated oxygen sensor 

(front). Then go to Step 12.

AK303830

1

2

3

4

AB

CONNECTOR: B-36 

B-36 (GR)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (FRONT)

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624 AB

MB991316

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

BLUE

RED

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-349

STEP 3. Measure the power supply voltage at cylinder 2, 3 
heated oxygen sensor (front) harness side connector B-36.
(1) Disconnect the connector B-36 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 5.
NO :  Go to Step 4.

STEP 4. Check harness connector B-17X at the MFI relay 
for damage.
Q: Is the harness connector in good condition?

YES : Repair harness wire between MFI relay connector 

B-17X (terminal No. 4) and cylinder 2, 3 heated 
oxygen sensor (front) connector B-36 (terminal No. 1) 
because of open circuit or short circuit to ground. 
Then go to Step 12.

NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12. 

AK303830

1

2

3

4

AB

CONNECTOR: B-36 

B-36 (GR)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (FRONT)

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01496

B-36 HARNESS 
CONNECTOR: 
COMPONENT SIDE

1

2

3

4

AY

AK303806

2

1

3

4

AB

CONNECTOR: B-17X

B-17X

RELAY BOX
TRIANGLE 
MARK

HARNESS CONNECTOR:
COMPONENT SIDE