engine MITSUBISHI GALANT 1989 Service Repair Manual

13-274FUEL SYSTEM - On-Vehicle Inspection of MFI Components
CLOSED THROTTLE POSITION SWITCH
MlSYKAEl
Terminal
voltage
Throttle shaft
turning angle Engine control module
1
Throttle position
sensor connector
Component side
connector
Harness side
connector
6FU1355
OPERATION
l
The closed throttle position switch functions to
convert (to HIGH/LOW-level voltage) data as to
whether the accelerator is depressed or re
-
leased, and to input that voltage (as signals) to
the engine control module. The engine control
module, based upon those signals, regulates the
idle air control motor.
TROUBLESHOOTING HINTS
If there is an abnormal condition of the closed throt-
tle position switch switch output even though the results of the checking of the closed throttle posi-
tion switch harness and of the component itself in-
dicate a normal condition, the cause may be pre-
sumed to be one of the following.
lVoltage within the engine control module is ap-
plied, by way of the resistance, to the closed
throttle position switch.
When the foot is taken off the accelerator, the
closed throttle position switch is switched ON,
so the current is grounded.
As a result, the closed throttle .position terminal
voltage changes from HIGH to LOW level.
(1) Improper adjustment of the accelerator cable or
the automatic-cruise-control cable.
(2) Improper adjustment of the closed throttle posi-
tion switch (fixed SAS).
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13-276FUEL SYSTEM -On-Vehicle Inspection of MFI Components
CLOSED THROTTLE POSITION SWITCH
Termrnalvoltage
Throttle shaft
turning angle012092
a
1
Closed throttle
position switch
terminal Engine control module
ci
Closed throttle
position switch
6FU13 56
OPERATION
TROUBLESHOOTING HINTS INSPECTION-Using Scan toolRefer to
P.13-274.
HARNESS INSPECTIONL
P
1
I
:
I @ Harness side
connector
Closed throttle
position switch
terminal
L
Measure the power supply voltage of
the closed throttle position switch.
. Connector: Disconnected
. Ignition switch: ON
SENSOR INSPECTION(1) Disconnect the closed throttle position switch connector.
(2) Check the continuity between terminal
@I and sensor
ground.
IAccelerator pedalIContinuityI
IDepressedINon-conductive (a Q)I
ReleasedConductive (0 S2)I
(3) If out of specification, replace the closed throttle position
switch.
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FUEL SYSTEM -On-Vehicle Inspection of MFI Components13-277
CAMSHAFT POSITION SENSOR Multiport fuelM13Yuh
1 Output characteristic
I-cTime
One rotation of crankshaft position sensor injection relay
Component side Crankshaft
connector position sensor
2I14,
Crankshaft
position
sensor
connector
I_ /
i7; !
~\==, ’60,Giiz!! @ Harness side
connector Camshatt posItIon
sensor
Engine control module
A22
Q
6FU1255
OPERATION
l The camshaft position sensor functions to de-
tect the top dead center position of the No.1 cy-
linder and to convert those data to pulse signals
that are input to the engine control module. The
engine control module, based upon those sig-
nals, calculates the sequence of fuel injection.
TROUBLESHOOTING HINTS
If there is a malfunction of the camshaft position
sensor, the sequential injection will not be correct,
lThe power for the camshaft position sensor is
supplied from the multiport fuel injection relay
and is grounded to the vehicle body. The cam-
shaft position sensor, by intermitting the flow (to
ground) of the 5V voltage applied from the en-
gine control module produces pulse signals.
resulting in such problems as engine stalling, un-
stable idling, and poor acceleration.
5v---r-
ovL_--..---I2 --
Normal waveform INSPECTION
Using Oscilloscope
(1) Run the engine at an idle speed.
(2) Connect the probe to the oscilloscope pick-up point as
shown in the circuit diagram, and check the waveform.

FUEL SYSTEM -On-Vehicle Inspection of MFI Components13-279
CAMSHAFT POSITION SENSOR M13YlABl
@
Component side
connector
Output characteristic
WINo.45
) Time
One rotation of crankshaft position sensor
Multiport fuel
injection relay
Crankshaft position sensor
I3
Engine control module
7FUO493
OPERATION
TROUBLESHOOTING HINTS INSPECTION-Using Oscilloscope Refer to
P.13-277.
HARNESS INSPECTION
Harness side
connector Measure the power supply voltage.
. Connector: Disconnected
. Ignition switch: ON
7FUO496
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13-280FUEL SYSTEM -On-Vehicle Inspection of MFI Components
2
rHarness side
connector @
-----.
m
l----L
=s- 0
H
z/Q
=
7FVO497
P
3@ Harness srdeconnectorE 0
-0
4
0
c
7FVO498
Check for continuity of the ground
circuit.
. Connector: Disconnected
Repair theharness.
@WGround)
Check the output circuit voltage.
. Connector: Disconnected
. Ignition switch: ON
IVoltage (V)
1 4.8-5.2 (
CRANKSHAFT POSITION SENSOR
v] ) Output characteristic
LIaTime - One
rotation of crankshaft position sensor
OlROlO3
Multiport fuel
injection relay @
Component side Crankshaft position
connector @
Harness side
), 27Engine control module
MIOYYAAI
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FUEL SYSTEM - On-Vehicle Inspection of MFI Components13-281
OPERATION
l
The crankshaft position sensor functions to de-
tect the crank angle (position) of each cylinder,
and to convert those data to pulse signals,
which are then input to the engine control mod-
ule. The engine control module, based upon
those signals, calculates the engine rpm, and
also regulates the fuel injection timing and the
ignition timing.
TROUBLESHOOTING HINTS
Hint 1:
If an impact is suddenly felt during driving or the en-
gine suddenly stalls during idling, try shaking the
crankshaft position sensor during idling.
If the engine stalls, the cause may be presumed to
be improper or incomplete contact of the crank-
shaft position sensor’s connector.
Hint 2:
If the crankshaft position sensor output rpm is 0
rpm during cranking when the engine cannot be
started, the cause may be presumed to be a mal-
function of the crankshaft position sensor or a bro-
ken timing belt.
Hint 3:
If the indicated value of the crankshaft position sen-
sor output rpm is 0 rpm during cranking when the
engine cannot be started, the cause may be pre-
INSPECTION
Using Scan tool l
The power for the crankshaft position sensor is
supplied from the ignition switch-IG
and is
grounded to the vehicle body. The crankshaft
position sensor, by intermitting the flow (to
ground) of the 5V voltage applied from the en-
gine control module, produces pulse signals.
sumed to be a failure of the ignition coil’s primary
current to intermittently pulse correctly, so a mal-
function of the ignition system circuitry, the ignition
coil and/or the power transistor is the probable
cause. Hint 4:
If idling is possible even though the crankshaft posi-
tion sensor indicated rpm is a deviation from the
standard value, the cause is usually a malfunction of
something other than the crankshaft position sen-
sor.
Examples:
(1) Malfunction of the coolant-temperature sensor.
(2) Malfunction of the idle air control motor.
(3) Improper adjustment of the standard idling
speed.
Inspection conditions
Description Normal condition
. Engine: CrankingCompare crankingBoth agree.. Tachometer connectionrpm and scan tool(Check intermittent flow ofindicated rpm.ignition coil primary current
by tachometer.)
burn No. / ~i~~~~,,Inspection conditions
At 40°C (104°F)
At 80°C (176°F)
1 ,OOO- 1,250 rpm
650-850 rpm 700-900 mm >
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I

13-282FUEL SYSTEM - On-Vehicle Inspection of MFI Components
(1) Run the engine at an idle speed.
-1 Using Oscilloscope(2) Connect the probe to the oscilloscope pick-up point asshown in the circuit diagram, and check the waveform.
!A--- - - - - - -
ov--------Normal waveform
I0310202
Measure the power supply voltage.asure the power supply voltage.
. Connector: Disconnected. Ignition switch: ON
HARNESS INSPECTION
1
Harness side
connector
I=I
Check for continuity of the ground
circuit.
. Connector: Disconnected
Repair the
harness.
K&III-Ground)
131Harness side@
connector
TSB RevisionCheck the voltage of the
output
cir-
cuit.
. Connector: Disconnected. Ignition switch: ON
ir
Repair theharness.

FUEL SYSTEM -On-Vehicle Inspection of MFI Components
CRANKSHAFT POSITION SENSOR
[VI 1 Output characteristic
One rotation of crankshaft position sensor
01R0’03
Engine controlmqdule21
R5VJ7FUO499I

Multiport fuel
injection relay
@ Component sid
e
connector
MlBYhlABl
OPERATION
TROUBLESHOOTING HINTS
INSPECTION-Using Scan tool
INSPECTION-Using Oscilloscope
Refer to
P.13-281.
HARNESS INSPECTION
11 I
1’1
Measure the power supply voltage.
@Harness
side. Connector: Disconnected
connector Ignition switch: O
N
Voltage (VI
Battery positive voltage
-
7FUO496
Repair theharness.-+ (@a-Multi-port fuel in-jection relay)
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FUEL SYSTEM -On-Vehicle Inspection of MFI Components13-285
AIR CONDITIONING SWITCH AND A/C COMPRESSOR CLUTCH RELAYmt3n7.4al
Jk: L 1 /J l-k~-~+ L!- Air conditioning switch
0
/’
’ ’ -~.i>
‘\ /,
(\ QeF --:
’ -q,,T
(‘a/ A-.,>*/ \
) !I/ ,+f---J;I’,,p
s- / :\,$jy W/’
\mc-- -; --
\\ \\$ &
IF -~1. bI /~-~ i E--z
\ \I i
!
L-,-1&L.- ~~~~.
6FUO845 I
Sub fusible link
‘7 IpI Z%37°GZressor
2 Dual pressure
switch
1
t
Air conditioning OFF
engif’Ie codant* temperatureON switc
h
T
2
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Engine control module
,(65 1\7
v v
Engine control module connector6FU1457
OlLo838
OPERATION
l
The air conditioning switch applies battery vol-
tage to the engine control module when the
air
conditioning is switched ON.
TROUBLESHOOTING HINTS
If the air conditioning compressor’s magnetic clutch
is not activated when the air conditioning switch
is switched ON during idling, it is probable that the
.When the air conditioning signals are input, the
engine control module activates the idle air con-
trol motor, and also switches ON the power
transistor. As a result, current flows to the A/C
compressor clutch relay coil and the relay
switch is switched ON, the air conditioning
compressor’s magnetic clutch is activated.
cause is a malfunction of the air conditioning control
system.

13-286FUEL SYSTEM - On-Vehicle Inspection of MFI Components
INSPECTION Using Scan tool
Air conditioning switch
Function Item No.
Data reading 28
Data displayCheck conditionsAir conditioning switchNormal
display
Switch status
. Engine idlingOFF OFF
(The air conditioning
compressor should beONONactivated when the air
conditioning switch is
switched ON.)
Air conditioning compressor clutch relay
Function
Item No.
Data reading 49
Data display
Check conditionsAir conditioning switchNormal display
Air condition-
. Engine: idling afterOFFOFF (Compressor
ing compres-warm up clutch non-
sor clutch
activation)
relay status ON
ONKompressorclutch activation)
HARNESS INSPECTION________ --- -__-. -- ~~-
Measure the power supply voltage of
the air conditioning circuit.
. Engine control module connec-tor: Disconnected- Ignition switch: ON+ Air conditioning switch: ON
side connector
AIR CONDITIONING INSPECTION
Refer to GROUP 55-Air Conditioning.
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