FUEL SYSTEM -On-Vehicle Inspection of
MFI Components13-299
OPERATION
l The amount of air taken in during idling is
regulated by the opening and closing of the
servo valve located in the air passage that
bypasses the throttle valve.
l The servo valve is opened or closed by the
activation of the stepper motor (incorporated
within the idle air control motor) in the forward
or reverse direction.
TROUBLESHOOTING HINTS
Hint 1: If the number of stepper motor steps increases to
IOO- 120 steps or decreases
to 0 step, the cause may be presumed to be a malfunction of the stepper motor or
damaged or disconnected wiring of the
harness.
Hint 2: If the number of stepper motor steps
deviates from the standard value even
though the results of the checking of the
harness of the idle air control motor and of
the comoonent
itself indicate no abnormal
condition, the cause may be presumed to be one of the following.
INSPECTION
Using Scan tool
lBattery power supply is supplied, by way of the
multiport fuel injection relay, to the coil of the
stepper motor. The engine control module
switches ON the power transistors (located
within the engine control module) in sequential
order, and, when current flows to the stepper motor coil, the stepper motor is activated in the
forward or reverse direction.
(1) Improper adjustment of the standard
idling speed.
(2) Deposits adhered to the throttle valve.
(3) Leakage of air into the intake manifold
from a gasket gap, etc.
(4) Incomplete close contact of the EGRvalve seat.
(5) Incomplete combustion within the
cylinder.
(Malfunction of the spark plugs, the
ignition coil, the iniectors,
the
com- pression
pressure, etc.)
FunctionItem No.Data display Check conditions Load conditionsStandard value
Data reading 45Steppermotor steps. Engine coolant tempera-
. Air conditioning
4-14Step
ture:switch: OFF 85-95°C
(185-205°F)
. Lights, electrical cooling
:$b::pfan and accessories: OFF
. Transaxle: neutral
. Closed throttle switch: ON
- Air conditioning 20-60 Step
switch: ON
(The compressor clutchshould be activated when
the air conditioning switch;J-;;o~P
is switched ON.)* Engine: idling
1;:!,1;:!,
/!-I\/!-I\
f$&$:”f$&$:”
! ,‘,! ,‘,
4);4);
;jj\(Q(j!jGZ-);jj\(Q(j!jGZ-)
lili
q#Q~Hq#Q~HF]F]
ii 2 L J 2 L ~ -0SClllO 4ii 2 L J 2 L ~ -0SClllO 4
NOTE
When the vehicle is new (driven approximately 500 km (300 miles) or l\
ess) the number of steps may be about
30 steps greater than the standard value indicated above.
Using Oscilloscope
(1) Connect the probe to each oscilloscope pick-up point as
shown in the circuit diagram.
(2) Start the engine.
(3) When the air conditioning switch is turned on, the idling speed increases to operate the idle air control. Check theinstantaneous waveform.
NOTE
Keep in mind that the waveform can be observed only
when idle air control is in operation.
23-44AUTOMATIC TRANSAXLE - Troubleshooting
INSPECTION OF ELECTRONIC CONTROL SYSTEM COMPONENTS1. Wiring Based on the wiring diagram,
improper connection of
check whether the continuity and connector, damaged or
disconnected harness,
grounding of each harness IS OK. or incorrect wiring con-4
nection.
cContinuity> 4
4
Reconnect the connec-
I
Normal
Itor; repair or replace the
harness.
2. Oil-temperature
sensortemperature and check theresist-ante between the terminals 1 and2 (FWD),1and2 or 2 and 3 Damaged
or disconnected
Replace the oil-
temperature sensor
FWD (1993 model)
TFA0821
AWD (Up to 1992 model) 1
1. Low temperature side
~
2. Ground
3. High temperature side
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33B-76 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
CONFIGURATION DIAGRAMS ENGINE ROOM
A-l 1 A-12 A-54
A-28
A-27
2:;. Refer to CENTRALIZED JUNCTIONIA-l 1ACTIVE-ECS exhaust solenoid valve
A-l 2 ACTIVE-ECS air compressor A-23
ACTIVE-ECS
G sensor A-27 ACTIVE-ECS front vehicle height sensor
A-28
ACTIVE-ECS flow-control solenoid valve A-37
ACTIVE-ECS return pump A-38
ACTIVE-ECS pressure switch A-39
ACTIVE-ECS air compressor relay
A40 ACTIVE-ECS return pump relayA-41 Front wiring harness and battery
cable combination A-50
ACTIVE-ECS front actuator A-54
Throttle position sensor (1989 models) A-58
ACTIVE-ECS front solenoid valve A-63
ACTIVE-ECS front actuator
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