Mitsubishi Galant 9G. Manual - part 696

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-226

STEP 2. Check the cylinder 1, 4 heated oxygen sensor
(front).
(1) Disconnect the cylinder 1, 4 heated oxygen sensor (front)

connector B-37 and connect test harness special tool
MB991316 to the connector on the cylinder 1, 4 heated
oxygen sensor (front) side.

(2) Warm up the engine until engine coolant temperature

reaches 80

°C (176°F) or higher.

(3) Perform a racing 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 cylinder

1, 4 heated oxygen sensor (front) output voltage.

Standard value: 0.6

− 1.0 volt

CAUTION

• Be very careful when connecting the jumper wires;

incorrect connection can damage the heated oxygen
sensor.

• Be careful the heater is broken when voltage of beyond

8 volts is applied to the heated oxygen sensor heater.
NOTE: If the sufficiently high temperature [of approximate
400

C (752

F) or more] is not reached although the heated

oxygen sensor is normal, the output voltage would be possi-
bly low although the rich airfuel ratio. Therefore, if the out-
put voltage is low, use a jumper wire to connect the terminal
No. 1 (red clip) and the terminal No. 3 (blue clip) of the
heated oxygen sensor with the positive terminal and the
negative terminal of 8 volts power supply respectively, then
check again.

Q: Is the measured voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.
NO : Replace the cylinder 1, 4 heated oxygen sensor

(front). Then go to Step 4.

AK303821

CONNECTOR: B-37

CYLINDER 1, 4
HEATED OXYGEN
SENSOR (FRONT)

B-37 (GR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MB991316

WHITE

BLACK

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-227

STEP 3. Check harness connector B-37 at cylinder 1, 4
heated oxygen sensor (front) and harness connector B-21,
B-22 at PCM for damage.
Q: Is the harness connector in good condition?

YES : Replace the PCM. Then go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 4.

AK303821

CONNECTOR: B-37

CYLINDER 1, 4
HEATED OXYGEN
SENSOR (FRONT)

B-37 (GR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303052

54 53 52 51

62 61 60 59 58

69 68 67 66 65 64

75 74 73 72 71

82 81 80 79 78 77

104

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTORS: B-21, B-22

B-21 HARNESS CONNECTOR:
COMPONENT SIDE

B-22 HARNESS CONNECTOR:
COMPONENT SIDE

PCM

AIR CLEANER

B-22 (B)

B-21 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-228

STEP 4. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function

− OBD-II Drive Cycle − Procedure 4 −

Heated Oxygen Sensor Monitor

P.13A-6

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0133 set?

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

DTC P0134: Cylinder 1, 4 Heated Oxygen Sensor No Activity Detected (sensor 1)

CAUTION

If DTC P0134 has been set, TCL related DTC
U1120 is also set. After P0134 has been diag-
nosed, don't forget to erase DTC U1120.

Cylinder 1, 4 Heated Oxygen Sensor
Circuit No Activity Detected (sensor 1)
Circuit

• Refer to DTC P0130 − Cylinder 1, 4 Heated Oxy-

gen Sensor (Front) Circuit

P.13A-192

• Refer to DTC P0201 − Injector Circuit-cylinder 1

P.13A-464

• Refer to DTC P0204 − Injector Circuit-cylinder 4

P.13A-494

CIRCUIT OPERATION

• Refer to DTC P0130 − Cylinder 1, 4 Heated Oxy-

gen Sensor (Front) Circuit

P.13A-192

• Refer to DTC P0201 − Injector Circuit-cylinder 1

P.13A-464

• Refer to DTC P0204 − Injector Circuit-cylinder 4

P.13A-494

TECHNICAL DESCRIPTION

• The PCM effects air/fuel ratio feedback control in

accordance with the signals from the cylinder 1, 4
heated oxygen sensor (front).

• If the cylinder 1, 4 heated oxygen sensor (front)

has deteriorated, corrections will be made by the
cylinder 1, 4 heated oxygen sensor (rear).

• DTC P0134 becomes stored in memory if a fail-

ure is detected in the above air/fuel ratio feed-
back control system.

DESCRIPTIONS OF MONITOR METHODS

Cylinder 1, 4 heated oxygen sensor (front) output

voltage does not cross 0.5 volt within specified
period.

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)

• Misfire monitor

Sensor (The sensor below is determined to be

normal)

• Mass airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-229

DTC SET CONDITIONS
Logic Flow Chart

Check Conditions

• 20 seconds or more have passed since the

engine starting sequence was completed.

• Engine coolant temperature is higher than 60°C

(140

°F).

• Engine speed is higher than 1,200 r/min.

• Volumetric efficiency is higher than 30 percent.

• Throttle position sensor output voltage is lower

than 4 volts.

• Except while fuel is being shut off.

• Monitoring time: 30 seconds.

Judgment Criteria

• Cylinder 1, 4 heated oxygen sensor (front) output

voltage does not get across 0.5 volt within about
30 seconds.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function

− OBD-II Drive Cycle −

Procedure 6

− Other Monitor

P.13A-6

HEATED OXYGEN SENSOR (FRONT)

OUTPUT VOLTAGE CROSSES 0.5V?

START

END

YES

Yes

YES

MALFUNCTION

GOOD

30secs HAVE PASSED?

MONITORING

CONDITIONS

AK203999

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