Mitsubishi Galant 9G. Manual — part 647

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

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SYSTEM READINESS TEST STATUS

PURPOSE

The Readiness function (also referred to as I/M
Readiness or I/M Flags) indicates if a full diagnostic
check has been "Completed" (is "Ready") for each
non-continuous monitor. Enhanced I/M State Emis-
sion Programs will use the Readiness status (Codes)
to see if the vehicle is ready for OBD-II testing.
"Incomplete" (Not Ready) codes will be one of the
triggers for I/M failure.

OVERVIEW

The PCM monitors the following main diagnosis
items and records whether the evaluation was com-
pleted or is incomplete. The Readiness Codes are
established for the I/M programs, thereby confirming
that the vehicles have not been tampered with by
erasing the diagnostic trouble code(s) (DTCs) before
I/M testing. The Readiness Codes and DTCs can be
reset by disconnecting the battery or by erasing the
codes with a scan tool MB991958 (MUT-III sub
assembly). For this reason, all the Readiness Codes
must be displayed "Complete" before I/ M testing.
When the monitors run and complete, the scan tool
MB991958 (MUT-III sub assembly) will display the
Readiness Codes as "Complete" (General Scan
Tools display as "Ready"). When the vehicle is oper-

ating normally and the OBD-II Drive Cycle is carried
out, the Readiness Codes will be set as "Complete"
on the first drive cycle. For DTCs requiring two drive
cycles to detect a fault, the second drive cycle is
required to set the Readiness Codes as "Complete"
if a fault is detected during the first drive cycle. If the
fault is still there after the second drive cycle, a DTC
will be set.

• Catalyst: P0421, P0431

• Evaporative system: P0442, P0455, P0456

• Heated oxygen sensor: P0130, P0131, P0132,

P0133, P0134, P0136, P0137, P0138, P0139,
P0150, P0151, P0152, P0153, P0154, P0156,
P0157, P0158, P0159

• Heated oxygen sensor heater: P0135, P0141,

P0155, P0161

• EGR system: P0401

After all the Readiness Codes are displayed as
"Complete", the technician is assured that any DTCs
related to the monitor will be displayed if the system
has a problem. That is why some State's I/M pro-
grams require the Readiness Code as "Complete"
before they check for DTCs.
NOTE: After a repair is made for a DTC, the techni-
cian should drive the OBD-II Drive Cycle checking
that the scan tool MB991958 (MUT-III Sub Assem-
bly) displays all the Readiness Codes as "Complete"

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

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FAIL-SAFE FUNCTION REFERENCE TABLE

M1131153000374

When the main sensor malfunctions are detected by
the diagnostic test mode, the vehicle is controlled by
means of the following defaults.

MALFUNCTION ITEM

CONTROL CONTENTS DURING MALFUNCTION

Mass airflow sensor

• Uses the throttle position sensor signal and engine speed signal (crankshaft

position sensor signal) for basic injector drive time and basic ignition timing
from the pre-set mapping.

Intake air temperature
sensor

Controls as if the intake air temperature is 25

°C (77°F).

Engine coolant
temperature sensor

Controls as if the engine coolant temperature is 80

°C (176°F). (This control will

be continued until the ignition switch is turned to " LOCK " (OFF) position even
though the sensor signal returns to normal.)

Camshaft position sensor Injects fuel into the cylinders in the order 1-3-4-2 with irregular timing. (After the

ignition switch is turned to the "ON" position, the No. 1 cylinder top dead center
is not detected at all.)

Barometric pressure
sensor

Controls as if the barometric pressure is 101 kPa (30 in.Hg).

Knock sensor

Switches the ignition timing from ignition timing for high octane to ignition timing
for standard octane fuel.

Heated oxygen sensor
<front>

Air/fuel ratio closed loop control is not performed.

Heated oxygen sensor
<rear>

Performs the closed loop control of the air/fuel ratio by using only the signal of
the heated oxygen sensor (front) installed on the front side of the catalytic
converter.

Generator FR terminal

No generator output suppression control is performed for the electrical load (to
be operated as an ordinary generator).

Misfire detection

The PCM stops supplying fuel to the cylinder with the highest misfiring rate if a
misfiring that could damage the catalytic converter is detected.

Accelerator pedal position
sensor (main)

• Detects the amount of the accelerator pedal travel through the use of the

accelerator pedal position sensor (sub) signal, but rendering it only as being
approximately one-half the normal opening angle.

• Prohibits the operation of the auto-cruise control.

• Cuts off fuel when the engine speed exceeds 3,000 r/min.

• Suppresses the engine output by stopping the electronically controlled

throttle valve system if the accelerator pedal position sensor (sub) is also
malfunctioning.

Accelerator pedal position
sensor (sub)

• Detects the amount of the accelerator pedal travel through the use of the

accelerator pedal position sensor (main) signal, but rendering it only as being
approximately one-half the normal opening angle.

• Prohibits the operation of the auto-cruise control.

• Cuts off fuel when the engine speed exceeds 3,000 r/min.

• Suppresses the engine output by stopping the electronically controlled

throttle valve system if the accelerator pedal position sensor (main) is also
malfunctioning.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

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Throttle position sensor
(main)

• Controls the throttle valve position through the use of the throttle position

sensor (sub) signal.

• Renders the amount of accelerator pedal travel as being approximately

one-half the normal opening angle.

• Prohibits the operation of the engine speed feedback control.

• Prohibits the operation of the auto-cruise control.

• Cuts off fuel when the engine speed exceeds 3,000 r/min.

• Suppresses the engine output by stopping the electronically controlled

throttle valve system if the throttle position sensor (sub) is also
malfunctioning.

Throttle position sensor
(sub)

• Controls the throttle valve position through the use of the throttle position

sensor (main) signal.

• Renders the amount of accelerator pedal travel as being approximately

one-half the normal opening angle.

• Prohibits the operation of the auto-cruise control.

• Cuts off fuel when the engine speed exceeds 3,000 r/min.

• Prohibits the idle speed control from learning.

• Suppresses the engine output by stopping the electronically controlled

throttle valve system if the throttle position sensor (main) is also
malfunctioning.

Throttle valve position
feedback

• Suppresses the engine output by stopping the electronically controlled

throttle valve system.

• Prohibits the operation of the auto-cruise control.

• Prohibits the operation of the engine speed feedback control.

Throttle actuator control
motor

• Suppresses the engine output by stopping the electronically controlled

throttle valve system.

• Prohibits the operation of the auto-cruise control.

• Prohibits the operation of the engine speed feedback control.

Throttle actuator control
computer

• Suppresses the engine output by stopping the electronically controlled

throttle valve system.

• Prohibits the operation of the auto-cruise control.

• Prohibits the operation of the engine speed feedback control.

Communication between
throttle actuator control
computer and engine
control computer

• Renders the amount of accelerator pedal travel as being approximately

one-half the normal opening angle.

• Prohibits the operation of the auto-cruise control.

• Prohibits the operation of the engine speed feedback control.

• Cuts off fuel when the engine speed exceeds 3,000 r/min.

Switching to high-speed
cam in mitsubishi
innovative valve timing
and lift electronic control

• Do not switch to high-speed cam.

• Cut off fuel when the engine speed exceeds 5,000 r/min.

MALFUNCTION ITEM

CONTROL CONTENTS DURING MALFUNCTION

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

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DIAGNOSTIC TROUBLE CODE CHART

M1131151001489

CAUTION

During diagnosis, a DTC associated with other
system may be set when the ignition switch is
turned on with connector(s) disconnected. On
completion, confirm all systems for DTCs. If
DTCs are set, erase them all.

DTC

DIAGNOSTIC ITEM

REFERENCE
PAGE

P0069

Abnormal correlation between manifold absolute pressure sensor and
barometric pressure sensor

P.13A-41

P0101*

Mass airflow circuit range/performance problem

P.13A-46

P0102*

Mass airflow circuit low input

P.13A-55