Toyota COMPUTER-CONTROLLED SYSTEM - Page 164

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TROUBLESHOOTING - Symptom Char t
POSSIBLE CAUS
E
SYMPTOM
SYSTEM
COMPONENT PART TYPE OF TROUBL E
Ai induction s stem
ISC valve
Won't open fully ,
r y
Air valve
won't open at al l
t id l N f as e o
Electronic control
Water temp . sensor Open or sho rt circui t
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 valv e
high
Manifold pressur e
sensor ( vacuum sensor)
Voltage or resistanc e
are incorrec t
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 resistanc e
Idle speed too
sensor ( vacuum sensor)
are incorrect, open o
r
low
Electronic control
sho rt circui t
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 injec t
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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