Page 305 of 1273

FUEL SYSTEM - :::,:k:t?=tiion Of MF’13-163
INSPECTION
Using Scan Tool
Function
( Item No.
Data reading
/ 5
5
l-
+
L
Data display
IAC valve
position step
TCheck condition
l Engine coolant tem- perature: 85 to
95°C
(185 to 203’F)l Lights, electric cool- ing fan, accesso-
ries: OFF
l Transaxle: Neutral
(P range for A/T)
l Closed throttle posi-
tion switch: ON
l Engine: At idle
(Compressor clutch
to be operating in case air conditioning
switch is ON) Load state
Air conditioning switch:
OFF
Air conditioning switch:
Turn from OFF to ON l Air conditioning switch: OFF
l Selector lever: Shift to
D range
,,,,,,,,,I
Increase from 3-40 I
step
NfOTE
In a new vehicle [driven approximately 500 km (300 miles) or less], th\
e IAC valve position sometimes exceeds the
standard value by approximately 20 steps.
Caution
When shifting the selector lever to the
D range, apply brake to prevent the vehicle from moving forward.
HARNESS INSPECTION
IIL\-11 r@Harm ” ’ -conna
tA Engine control
-tmodule harnessside rnnnnctor
Check for open circuit, or short-circuit
to ground, between engine control module and
IAC valve position sensor.
l Engine control module connec- tor: Disconnected
l
IAC valve position sensor connec-
tor. Disconnected
21
@Harness sideconnector
0,OK-& 121
i Repair the
--L
harness
(@lcl- El)
/ ml-~) (@pJ
- @I)
Check for continuity of the ground
circuit.
l
IAC valve position sensor connec-
tor: Disconnected
Page 306 of 1273
13-164
On-Vehicle Inspection of MFI
FUEL SYSTEM
(SOHC-16 VALVE> - Components
Measure the impressed voltage.
lIAC valve position sensor connec-
tor: Disconnected
l Engine control module connec-
tor: Connected
*6FU1724
$Harness side
connector
Measure the impressed voltage.
l
IAC valve position sensor connec-
tor: Disconnected
*
Engine control module connec-
tor: Connected
l Ignition switch: ON 6FU1723
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1
Page 307 of 1273

FUEL SYSTEM (SOHC-16 VALVE> - %$k%lnspectio” Of MF’13-165
CAMSHAFT POSITION SENSOR
@ Equipment side
connector
Output
characteristic PJ)
‘One rotation of distributor
@ Harness stdeconnector
lgnltion switch (IG,)
Distributor pistributor& 2 ,
I
z
Camshaft
position
Engine
control
module
Engine control module connector
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7FUO6539FuOO27
OPERATION
l The camshaft position sensor detects the top dead
center
on the
compression
stroke
of
the
No.1 cylinder, converts it into a pulse signal and
inputs it to the engine control module. The en-
gine control module determines the fuel injec-
tion sequence based on this signal.
l Power to the camshaft position sensor is sup-
plied from the ignition switch (IG), and the
ground is located in the engine control module.
A
5V voltage is applied from the engine control
module to the camshaft position sensor output
terminal, and the camshaft position sensor gen-
erates a pulse signal as it switches from OPEN
to SHORT (power transistor inside the sensor
switches ON/OFF) between the output terminal
and the ground. TROUBLESHOOTING HINTS
Hint 1: If the camshaft position sensor is defective, proper sequential injection will not occur, so
the engine will stall, or unstable idling and poor acceleration will occur.
Hint 2: When the camshaft position sensor outputs a pulse signal when the ignition switch is
turned to ON (without starting the engine),
the camshaft position sensor or engine con-
trol module is probably defective.
Page 308 of 1273
13-166
On-Vehicle Inspection of MFI
FUEL SYSTEM
- Components
INSPECTION
Using Oscilloscope Refer
to P.13-69.
HARNESS INSPECTION
c
IIlFUO633j switch
1218 Harness -.-..-Aside
connectorCheck for continuity of the ground
circuit.
l Crankshaft
position sensor connec-
tor: Disconnected
Ground) lFUO634
I
3:
@ Harnessside connectorfF
68
Engine control
module harness
side connector
J 9P-
l Crankshaft position sensor connec-
tor: Disconnected
9FUOO29 II
Check for open circuit or short circuit
to ground, between camshaft position
sensor and engine control module.
l Engine control module connec- tor: Disconnected
Measure the impressed voltage.
l Crankshaft position sensor connec- tor: Disconnected
l Engine control module connec-
tor: Connected
l ignition switch: ON
Voltage
(V)
4.8 - 5.2 module
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Page 309 of 1273
FUEL SYSTEM
VALVE> - ::ii,,:::ti=pection Of MF’13-167
CRANKSHAFT POSITION SENSOR
@ Equipment
side connector
Output characteristic (V)
::
L*Time
One rotation of distributor
01R0103
Engine control module connector
@ Harness sideconnector
Enginecontrol
module
Ignition switch (IG,)
IDistributor
Crankshaft position
sensorI/\2
B
/\
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Oscillo
1 I”69 ,.68
I
IL hh5V5v 7FUO653
9FUOO27
Page 310 of 1273

13-168FUEL SYSTEM - ::ii$%%spection Of MF’
OPERATION
l The crankshaft position sensor detects thecrank angle (piston position) of each cylinder,
converts it to a pulse signal and inputs it to the
engine control module. The engine control mod- ule computes the engine speed and the intake
air amount for one stroke and outputs the injec-
tor drive signal and injection command signal
based on this signal.
0Power to the crankshaft position sensor is sup-
plied from the ignition switch
(IG), and the
ground is located in the engine control module.
A
5V voltage is applied from the engine control
module to the crankshaft position sensor output
terminal, and the crankshaft position sensor generates a pulse signal as it switches from
OPEN to SHORT (power transistor inside the
sensor switches ON/OFF) between the output
terminal and the ground. TROUBLESHOOTING HINTS
Hint
1: If unexpected shocks are felt during driving or the engine stalls suddenly during idling,
shake the crankshaft position sensor har- ness. if this causes the engine to stall, poor
contact of the sensor connector is sus-
pected.
Hint 2: If the crankshaft position sensor outputs a
pulse signal when the ignition switch is
turned to ON, (without starting the engine),
the crankshaft position sensor or engine control module is probably defective.
Hint 3: If the tachometer reads 0 rpm when the en- gine that has failed to start is cranked, faulty
crankshaft position sensor or broken timing
belt is suspected.
Hint 4: If the tachometer reads 0 rpm when the en- gine that has failed to start is cranked, theprimary current of the ignition coil is not
turned on and off. Therefore, troubles in the ignition circuit and ignition coil or faulty igni-
tion power transistor is suspected.
Hint 5: If the engine can be run at idle even though
the crankshaft position sensor reading is out
of specification, troubles are often in other
than the crankshaft position sensor. [Examples]
(1) Faulty water temperature sensor
(2) Faulty idle air control motor
(3) Poorly adjusted basic idle speed
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Page 311 of 1273
FUEL SYSTEM (SOHC-16 VALVE> - :::%%t:nspection Of MF’13-169
INSPECTION
Using Scan Tool
i
t
/FunctionItem No. i Data display Check condition Check content
Normal state
Data reading
) 22( Cranking l Engine cranking
speed l Tachometer con-’ Compare cranking speed, Indicated speed to
and scan tool reading agree
netted (check on and ~
I
off of primary current 1
of ignition coil by1
tachometer)
Function 1
Item No. Data display ICheck condition !Check content Normal state
Data reading
i 22 ~
Idle speed l Engine: idling! l Closed throttle posi-
tion switch: ONp i ;;:;;:::;;:;;;
20°C (68°F)1 l,lOO-1,300 rpm
40°C
(I
04°F)950-I ,I 50 rpm
: 80°C (176°F) ~
600-800 rpm
I
Using Oscilloscope
Refer to P.13-74.
Page 312 of 1273
13-170FUEL SYSTEM - ::$%:ti=pection Of MF’
HARNESS INSPECTION
III@ HarnessMeasure the power supply voltage.-/-J side connectorl Crankshaft position sensor connec-
tor: Disconnected
l Ignition switch: ON
Voltage
(VI
Repair the
hahrness
(@a - Igni-
B+tion switch)
or check the
ignition
lFUO633 !switch
1 FU0634
side connectorside connector
Engine control module
Engine control moduleharness side connect01harness side connect01
9FUOO30
Check for continuity of the ground
circuit.
l Crankshaft position sensor connec- tor: Disconnected
1 Repair th
e
Check for open circuit, or short-circuit
to ground, between crankshaft posi-
tion sensor and engine control mod-
ule.
l Engine control module connec-
tor: Disconnected
l Crankshaft position sensor connec-
tor: Disconnected ~
Repair the
+ harness
/ @El-El)
*
lFUO637
Measure the impressed voltage.
l Crankshaft position sensor connec- tor: Disconnected
l Engine control module connec-
tor: Connected
l Ignition switch: ON
1 TSB Revision