Mitsubishi Galant 9G. Manual - part 978

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-212

STEP 14. Check the right bank heated oxygen sensor
(front).

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

connector B-09 and connect test harness special tool,
MD998464, to the connector on the right bank 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 right

bank 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 air/fuel 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 voltage between 0.6 and 1.0 volt?

YES : Replace the PCM. Then go to Step 15.
NO : Replace the right bank heated oxygen sensor (front).

Then go to Step 15.

AK303048

B-09 (B)

CONNECTOR: B-09

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-213

STEP 15. 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 6 −

Other Monitor

P.13B-6

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0130 set?

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

DTC P0131: Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 1)

BLA

BLUE

BLA

TO PCM

FROM MFI RELAY

PINK

AK400900

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

POWERTRAIN CONTROL
MODULE (PCM)

B-09

MU802605

B-22

Right Bank Heated Oxygen Sensor (front) Circuit

B-21

100

93 94 95

96 97 98

101 102 103 104

105 106 107 108

109 110 111 112 113

53 54 55 56

58 59 60 61 62

64 65 66 67 68 69

71 72 73 74 75

77 78 79 80 81 82

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-214

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 92) from the output terminal (terminal
No. 4) of the right bank heated oxygen sensor
(front).

• Terminal No. 2 of the right bank heated oxygen

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

TECHNICAL DESCRIPTION

• The right bank heated oxygen sensor (front)

detects the concentration of oxygen in the
exhaust gas; it converts those data to voltage,
and inputs the resulting signals to the PCM.

• When the right bank heated oxygen sensor

(front) begins to deteriorate, the heated oxygen
sensor signal response becomes poor.

• The PCM forcibly varies the air/fuel mixture to

make it leaner and richer, and checks the
response speed of the right bank heated oxygen
sensor (front). In addition, the PCM also checks
for an open circuit in the right bank heated oxy-
gen sensor (front) output line.

DESCRIPTIONS OF MONITOR METHODS

Right bank heated oxygen sensor (front) output volt-

age stays low when air/fuel ratio is forced to be
rich. The above procedure is repeated when oxy-
gen sensor is inactive.

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

• Misfire monitor

• Fuel system 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

• Accelerator pedal position sensor

AK303047

B-09 (B)

CONNECTOR: B-09

THROTTLE BODY

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK303013

CONNECTORS: B-21, B-22

PCM

AIR CLEANER

B-22 (B)

B-21 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-215

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• After 2 seconds or more pass from the time when

the monitor determines normally for detecting an
open circuit.

• Right bank heated oxygen sensor (front) signal

voltage has continued to be 0.2 volt or lower.

• Engine coolant temperature is higher than 76°C

(169

°F).

• Mass airflow sensor output is 8 g/sec or more.

START

> =4.5V

2secs HAS PASSED

YES

MALFUNCTION

MONITORING

CONDITIONS

YES

MONITORING

CONDITIONS

+5V ON

AK401409

< 0.2V

8secs HAS PASSED

YES

END

MALFUNCTION

GOOD

MODULATE A/F CONDITION TO RICH

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