Mitsubishi Galant 9G. Manual — part 935

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-40

Idling stability

Hunting

Engine speed doesn't remain constant; changes at idle.

Rough idle

Usually, a judgement can be based upon the movement of the
tachometer pointer, and the vibration transmitted to the steering wheel,
shift lever, body, etc.

Incorrect idle
speed

The engine doesn't idle at the correct speed.

Engine stall (die
out)

The engine stalls when the foot is taken from the accelerator pedal,
regardless of whether the vehicle is moving or not.

Engine stall
(pass out)

The engine stalls when the accelerator pedal is depressed.

At driving

Hesitation Sag

"Hesitation" is the delay in
response of the vehicle speed
(engine speed). This occurs when
the accelerator is depressed in
order to accelerate from the speed
at which the vehicle is now
traveling, or a temporary drop in
vehicle speed (engine speed)
during such acceleration.
Serious hesitation is called "sag".

Poor
acceleration

Poor acceleration is inability to obtain an acceleration corresponding to
the degree of throttle opening, even though acceleration is smooth.
Also the inability to reach maximum speed.

Stumble

Engine speed increase is delayed
when the accelerator pedal is
initially depressed for acceleration.

Shock

The feeling of a comparatively large impact or vibration when the
engine is accelerated or decelerated.

Surge

This is slight acceleration and deceleration feel usually felt during
steady, light throttle cruise. Most notable under light loads.

Knocking

A sharp sound during driving, which sounds like a hammer striking the
cylinder walls. It makes poor driveability.

At stopped

Run on
("Dieseling")

The condition in which the engine continues to run after the ignition
switch is turned to the "LOCK" (OFF) position. Also called "dieseling".

ITEMS

SYMPTOM

AKX01361

VEHICLE
SPEED

TIME

NORMAL

HESITATION

SAG

INITIAL
ACCELE-
RATOR
PEDAL
DEPRE-
SSION

AKX01361AB

AKX01362

VEHICLE
SPEED

TIME

NORMAL

STUMBLE

INITIAL
ACCEL-
ERATOR
PEDAL
DEP-
RESSION

IDLING

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-41

DIAGNOSTIC TROUBLE CODE PROCEDURES

DTC P0069: Abnormal Correlation Between Manifold Absolute Pressure Sensor And Barometric
Pressure Sensor

.

TECHNICAL DESCRIPTION

• The PCM detects abnormality in the sensor by

comparing the manifold absolute pressure sensor
output with the barometric pressure sensor out-
put.

.

DESCRIPTIONS OF MONITOR METHODS

The PCM compares the manifold absolute pressure

sensor output with the barometric pressure sen-
sor output while the engine control relay is in
"ON" position after the ignition switch is in
"LOCK" (OFF) position. When the difference
exceeds the specified value between them, the
PCM determines whether the manifold absolute
pressure sensor / the barometric pressure sensor
has malfunction or not.

.

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)

• Not applicable

Sensor (The sensor below is determined to be

normal)

• Not applicable

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-42

DTC SET CONDITIONS
Logic Flow Chart

Check Conditions

• Ignition switch is in "LOCK" (OFF) position.

• After two seconds pass from the time when the

engine is stopped.

• Engine coolant temperature is higher than 0°C

(32

°F).

Judgment Criterion

• Difference between manifold absolute pressure

sensor output and barometric pressure sensor
output is more than 9 kPa (2.7 in.Hg) for 2 sec-
onds.

.

OBD-II DRIVE CYCLE PATTERN

None.

.

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

• Manifold absolute pressure sensor failed.

• Barometric pressure sensor failed.

• PCM failed.

START

YES

YES

YES

NO

NO

NO

|BAROMETRIC PRESSURE | MANIFOLD

PRESSURE| > 9kPa (2.7in.Hg)

CONTINUOUS

FAILURE FOR 2secs

MALFUNCTION

END

GOOD

MONITORING

CONDITIONS

AK401533

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-43

DIAGNOSIS

Required Special Tools

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic
trouble code (DTC).

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) Turn the ignition switch to the "ON" position.

(3) Set scan tool MB991958, read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P0069 set?

YES : Refer to, Diagnostic Trouble Code Chart

P.13B-34

.

NO : Go to Step 2.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827