Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 164

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TROUBLESHOOTING - Symptom Chart
POSSIBLE CAUS E
SYMPTOM
SYSTEM
COMPONENT PART TYPE OF TROUBLE
Ai induction s stem
ISC valve
Won't open fully,
r y
Air valve
won't open at al l
t id l N fas e o
Electronic control
Water temp. sensor
Open or sho
rt
circuit
syste m
Cold sta
rt
system
Cold sta
rt
injector
Leakin g
Thro
tt
le body
Won't close full y
Air induction system
ISC valve
en continuous l Sta s o y y p
Idle speed too
Air valve
high
Manifold pressure
sensor ( vacuum sensor)
Voltage or resistanc e
are incorrect
Electronic control
Water temp . senso r
system
Thro
tt
le position sensor
Idle
contact won't go o n
Air conditioner switch
Stays on continuousl y
Air induction system ISC valve Stays close d
Rough idling
Manifold pressure
Voltage or resistance
Idle speed too
sensor (vacuum sensor)
are incorrect, open o r
low
Electronic control
sho
rt
circuit
system
Neutral sta
rt
switch
Won't
o o n
g
Air conditioner switc h
Fuel pump
Malfunctionin g
Fuel s stem
Injectors
Won't inject
y
Pressure regulator Malfunctionin g
Fuel filter, fuel line Clogge d
Thro
tt
le body Air suctio n
Air induction system ISC valve
Malfunctionin g
Air valv e
Unstable idlin g
Igniter
Malfunctionin g
Ignition system Ignition coil
( poor contact)
Spark plugs
Misfir e
Manifold pressure
Malfunctionin g
Electronic control
sensor (vacuum sensor )
system
Thro
tt
le position sensor
Idle
contact won't go o n
Oxygen (02) sensor Malfunctionin g
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