Mitsubishi Galant. Manual — part 234

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-161

STEP 1. Using scan tool MB991502, check data list item 11:
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK"(OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

11, Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

(4) Warm up the engine, 2500r/min.

•

Output voltage repeats 0.4 volt or less and 0.6

−

1.0 volt

10 times or more within 10 seconds.

(5) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points(

P.00-8

).

NO : Replace the left bank heated oxygen sensor (front).

Then go to Step 2.

STEP 2. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to,

Procedure 6

−

Other Monitor(

P.13B-4

).

(2) Check the diagnostic trouble code (DTC).

Q: Is the DTC P0153 is output?

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

DTC P0154: O

2

Sensor Circuit No Activity Detected (bank 2 sensor 1)

O

2

SENSOR CIRCUIT NO ACTIVITY DETECTED

(BANK 2 SENSOR 1) CIRCUIT

•

Refer to, DTC P0150

−

Left Bank Heated Oxygen

Sensor (front) Circuit (

P.13B-151

).

•

Refer to, DTC P0202, P0204, P0206

−

Injector

Circuit (

P.13B-220

).

CIRCUIT OPERATION

•

Refer to, DTC P0150

−

Left Bank Heated Oxygen

Sensor (front) Circuit (

P.13B-151

).

•

Refer to, DTC P0202, P0204, P0206

−

Injector

Circuit (

P.13B-220

).

TECHNICAL DESCRIPTION

•

The left bank heated oxygen sensor (front)
detects the concentration of oxygen in the
exhaust gas; it converts that data to voltage, and
sends it to the PCM.

•

When the left bank heated oxygen sensor (front)
begins to deteriorate, the heated oxygen sensor
signal response deteriorates also.

•

The PCM varies the air/fuel mixture to make it
leaner and richer, and checks the response
speed of the left bank heated oxygen sensor
(front). In addition, the PCM also checks for an
open circuit in the left bank heated oxygen sensor
(front) output line.

DTC SET CONDITIONS

Check Area

•

Thirty seconds or more have passed since the
starting sequence was completed.

•

Engine coolant temperature is higher than 81

°

C

(178

°

F).

•

Engine speed is higher than 1200 r/min.

•

Volumetric efficiency is higher than 30 percent.

•

Under the closed loop air/fuel control.

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-162

•

Monitoring time: 30seconds.

Judgment Criteria

•

Multiport fuel injection system does not enter the
closed loop control within about 30 seconds of
meeting all criteria above.

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

•

Left bank heated oxygen sensor (front)
deteriorated.

•

Open circuit in left bank heated oxygen sensor
(front) output line.

•

Open circuit in left bank heated oxygen sensor
(front) ground line.

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB998464: Test Harness

STEP 1. Check the exhaust leaks.

Q: Are there any abnormalities?

YES : Go to Step 2.
NO : Repair it. Then go to Step 11.

STEP 2. Check the intake system vacuum leak.

Q: Are there any abnormalities?

YES : Go to Step 3.
NO : Repair it. Then go to Step 11.

STEP 3. Check connector B-28 at the left bank heated
oxygen sensor (front) for damage.
Q: Is the connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 11.

AK000619

CONNECTOR:B-28

AB

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-163

STEP 4. Check the left bank heated oxygen sensor (front).
(1) Disconnect the left bank heated oxygen sensor (front)

connector B-28 and connect test harness special tool
MD998464 to the connector on the left bank heated oxygen
sensor (front) side.

(2) Warm up the engine until engine coolant 80

°

C (176

°

F) or

higher.

CAUTION

Be very careful when connecting the jumper wires;
incorrect connection can damage the left bank heated
oxygen sensor (front).
(3) Use the jumper wires to connect terminal 1 (red clip) to the

positive battery terminal and terminal 3 (blue clip) to the
negative battery terminal.

(4) Connect a digital volt meter between terminal 2 (black clip)

and terminal 4 (white clip).

(5) While repeatedly revving the engine, measure the left bank

heated oxygen sensor (front) output voltage.

Standard value: 0.6

−−−−

1.0 V

Q: Is the voltage at the standard value?

YES : Go to Step 5.
NO : Replace the left bank heated oxygen sensor (front).

Then go to Step 11.

STEP 5. Check connector B-17, B-21, B-30 at left bank
injector for damage.
Q: Is the connector in good condition?

YES : Go to Step 6.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 11.

ACX02489 AF

CONNECTOR:B-28

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01624

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

MD998464

BLUE

RED

AC

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464

AK000618 AD

CONNECTORS:B-17,B-21,B-30

B-30

B-17

B-21

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-164

STEP 6. Check the left bank injector.
(1) Disconnect the left bank injector connector B-17, B-21, B-

30.

(2) Measure the resistance between each injector side

connector terminal 1 and 2.

Standard value: 13

−−−−

16 ohm [at 20

°°°°

C (68

°°°°

F)]

Q: Is the resistance standard value?

YES : Go to Step 7.
NO : Replace the faulty injector. Then go to Step 11.

STEP 7. Check connector C-39, C-41 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 8.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 11.

AK000618 AD

CONNECTORS:B-17,B-21,B-30

B-30

B-17

B-21

AK000559

2

1

INJECTOR SIDE
CONNECTOR

AB

AK000280

CONNECTORS : C-39, C-41

C-39

C-41

PCM

AZ