Mitsubishi Galant (2004+). Manual - part 1147

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-281

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 97) from the output terminal (terminal 
No. 4) of the right bank heated oxygen sensor 
(rear).

• Terminal No. 2 of the right bank heated oxygen 

sensor (rear) is grounded with PCM (terminal No. 
69).

.

TECHNICAL DESCRIPTION

• The output signal of the right bank heated oxygen 

sensor (front) is compensated by the output sig-
nal of the right bank heated oxygen sensor (rear).

• The PCM checks for an open circuit in the right 

bank heated oxygen sensor (rear) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Right bank heated oxygen sensor (rear) output volt-

age does not change during specified go/stop 
operations including fuel cut are repeated.

.

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 heater (front) monitor

• Heated oxygen sensor heater (rear) monitor

• Air/fuel ratio feedback monitor

Sensor (The sensor below is determined to be 

normal)

• Mass airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

.

AK303063

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-08

B-08 (GR)

AB

AK303013

CONNECTORS: B-21, B-22

PCM

AB

AIR CLEANER

B-22 (B)

B-21 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-282

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine coolant temperature is higher than 76°C 

(169

°F).

• The right bank heated oxygen sensor (front) is 

active.

• The cumulative mass airflow sensor output is 

higher than 1638 g.

• Repeat 3 or more times: drive

*1

, stop

*2

.

Drive

*1

: 

• Engine speed is higher than 1,500 r/min.

• Volumetric efficiency is higher than 40 per-

cent.

• Vehicle speed is higher than 30 km/h (19 

mph).

• A total of more than 10 seconds have 

elapsed with the above mentioned condi-
tions, and more than 2 seconds have 
elapsed with the fuel shut off.

Stop

*2

:

• Vehicle speed is lower than 1.5 km/h (1.0 

mph).

Judgement Criteria

• Change in the output voltage of the right bank 

heated oxygen sensor (rear) is lower than 0.313 
volt.
NOTE: Monitoring stops after fuel has been shut 
off for more than 41 seconds.

.

END

YES

NO

NO

NO

START

MONITORING

CONDITION

YES

MALFUNCTION

GOOD

OUTPUT VOLTAGE 

CHANGE < 0.313 V

GO/STOP OPERATION

FOR SPECIFIED TIMES

YES

AK302399

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-283

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 4 

− Heated Oxygen Sensor Monitor 

P.13B-5

.

.

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

• Right bank heated oxygen sensor (rear) failed.

• Connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991316: Test Harness

STEP 1. Using scan tool MB991958, check data list item 69: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine and run at idle.

(3) Set scan tool MB991958 to the data reading mode for item 

69, Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

(4) Warm up the engine.

• After increasing the output voltage 0.15 volt or more by 

the engine revving, finish it. Then confirm that the output 
voltage reduces to 0.15 volt or less within 3 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.00-6

.

NO :  Replace the heated oxygen sensor (rear). Then go to 

Step 2. 

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-284

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

(1) Disconnect the right bank heated oxygen sensor (rear) 

connector B-08 and connect test harness special tool, 
MB991316, to the connector on the right bank heated 
oxygen sensor (front) side.

(2) Warm up the engine until engine coolant 80

°C (176°F) or 

higher.

(3) Perform a tracing for 5 minutes or more with the engine 

speed of 4,500 r/min.

(4) Connect a digital voltage meter between terminal No. 2 

(black clip) and terminal No. 4 (white clip).

(5) While repeatedly revving the engine, measure the right 

bank heated oxygen sensor (rear) output voltage.

Standard value: 0.6 

− 1.0 volt

CAUTION

• Be very careful when connecting the jumper wire; 

incorrect connection can damage the oxygen sensor.

• Be careful the heater is broken when voltage of beyond 

8V is applied to the oxygen sensor heater.
NOTE: If the sufficiently high temperature (of approximate 
400

°

C or more) is not reached although the oxygen sensor 

is normal, the output voltage would be possibly low 
although the rich air-fuel ratio. Therefore, if the output volt-
age is low, use a jumper wire to connect the terminal No.1 
(red clip of special tool) and the terminal No. 3 (blue clip of 
special tool) of the oxygen sensor with a (+) terminal and (-) 
terminal of 8 V power supply respectively, then check again.

Q: Is the voltage between 0.6 and 1.0 volt?

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

Then go to Step 4.

AK303064

1

2

3

4

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-08

B-08 (GR)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MB991316

WHITE

BLACK

AN