Mitsubishi Galant (2004+). Manual - part 891

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-381

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 96) from the output terminal (terminal 
No. 4) of the cylinder 2, 3 heated oxygen sensor 
(rear).

• Terminal No. 2 of the cylinder 2, 3 heated oxygen 

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

.

TECHNICAL DESCRIPTION

• The output signal of the cylinder 2, 3 heated oxy-

gen sensor (front) is compensated by the output 
signal of the cylinder 2, 3 heated oxygen sensor 
(rear).

• The PCM checks for an open circuit in the cylin-

der 2, 3 heated oxygen sensor (rear) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Cylinder 2, 3 heated oxygen sensor (rear) output 

voltage is over specified range.

.

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

.

AK303834AB

CONNECTOR: B-35

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

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) <2.4L ENGINE>

13A-382

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 2 seconds or more have passed since the engine 

starting sequence was completed.

Judgment Criteria

• Cylinder 2, 3 heated oxygen sensor (rear) output 

voltage has continued to be 1.2 volts or higher for 
2 seconds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-5

.

.

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

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

sor (rear) output line.

• 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

START

END

NO

NO

YES

YES

MALFUNCTION

GOOD

2secs HAVE PASSED?

OUTPUT VOLTAGE > 1.2V

NO

YES

MONITORING

CONDITIONS

AK302026

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-383

STEP 1. Check harness connector B-35 at cylinder 2, 3 
heated oxygen sensor (rear) and harness connector B-22 
at PCM 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 3.

AK303835

1

2

3

4

AB

CONNECTOR: B-35 

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK303016

104

96

94

95

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-384

STEP 2. Check for short circuit to power supply between 
cylinder 2, 3 heated oxygen sensor (rear) connector B-35 
(terminal No. 4) and PCM connector B-22 (terminal No. 96).

Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 3.
NO :  Repair it. Then go to Step 3.

AK303835

1

2

3

4

AB

CONNECTOR: B-35 

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK303016

104

96

94

95

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER