Page 4021 of 4592
![TOYOTA CAMRY 1999 Service Repair Manual To Ignition SW
IG Terminal
Fuse
Voltmeter SW 1
Relay
SW 2Solenoid[A]
[B]
[C]
Ohmmeter
SW
Ohmmeter
Diode
Digital Type Analog Type
C TROUBLESHOOTING
VOLTAGE CHECK
(a)Establish conditions in which volta TOYOTA CAMRY 1999 Service Repair Manual To Ignition SW
IG Terminal
Fuse
Voltmeter SW 1
Relay
SW 2Solenoid[A]
[B]
[C]
Ohmmeter
SW
Ohmmeter
Diode
Digital Type Analog Type
C TROUBLESHOOTING
VOLTAGE CHECK
(a)Establish conditions in which volta](/manual-img/14/57448/w960_57448-4020.png)
To Ignition SW
IG Terminal
Fuse
Voltmeter SW 1
Relay
SW 2Solenoid[A]
[B]
[C]
Ohmmeter
SW
Ohmmeter
Diode
Digital Type Analog Type
C TROUBLESHOOTING
VOLTAGE CHECK
(a)Establish conditions in which voltage is present at the check
point.
Example:
[A] ± Ignition SW on
[B] ± Ignition SW and SW 1 on
[C] ± Ignition SW, SW 1 and Relay on (SW 2 off)
(b)Using a voltmeter, connect the negative lead to a good ground
point or negative battery terminal, and the positive lead to the
connector or component terminal.
This check can be done with a test light instead of a voltmeter.
CONTINUITY AND RESISTANCE CHECK
(a)Disconnect the battery terminal or wire so there is no voltage
between the check points.
(b)Contact the two leads of an ohmmeter to each of the check
points.
If the circuit has diodes, reverse the two leads and check
again.
When contacting the negative lead to the diode positive side
and the positive lead to the negative side, there should be
continuity.
When contacting the two leads in reverse, there should be no
continuity.
(c)Use a volt/ohmmeter with high impedance (10 kW/V
minimum) for troubleshooting of the electrical circuit.
Page 4022 of 4592
![TOYOTA CAMRY 1999 Service Repair Manual To Ignition SW
IG Terminal
Test Light
Relay Light
SW 2 SolenoidDisconnectShort [A]
Disconnect
DisconnectSW 1Fuse Case
Short [B]
Short [C]
Pull Up
Press Down Press DownPull Up
C
FINDING A SHORT CIRCUIT TOYOTA CAMRY 1999 Service Repair Manual To Ignition SW
IG Terminal
Test Light
Relay Light
SW 2 SolenoidDisconnectShort [A]
Disconnect
DisconnectSW 1Fuse Case
Short [B]
Short [C]
Pull Up
Press Down Press DownPull Up
C
FINDING A SHORT CIRCUIT](/manual-img/14/57448/w960_57448-4021.png)
To Ignition SW
IG Terminal
Test Light
Relay Light
SW 2 SolenoidDisconnectShort [A]
Disconnect
DisconnectSW 1Fuse Case
Short [B]
Short [C]
Pull Up
Press Down Press DownPull Up
C
FINDING A SHORT CIRCUIT
(a)Remove the blown fuse and disconnect all loads of the fuse.
(b)Connect a test light in place of the fuse.
(c)Establish conditions in which the test light comes on.
Example:
[A] ± Ignition SW on
[B] ± Ignition SW and SW 1 on
[C] ± Ignition SW, SW 1 and Relay on (Connect the
Relay) and SW 2 off (or Disconnect SW 2)
(d)Disconnect and reconnect the connectors while watching the
test light.
The short lies between the connector where the test light
stays lit and the connector where the light goes out.
(e)Find the exact location of the short by lightly shaking the
problem wire along the body.
CAUTION:
(a) Do not open the cover or the case of the ECU unless
absolutely necessary. (If the IC terminals are touched,
the IC may be destroyed by static electricity.)
(b) When replacing the internal mechanism (ECU part) of
the digital meter, be careful that no part of your body or
clothing comes in contact with the terminals of leads
from the IC, etc. of the replacement part (spare part).
DISCONNECTION OF MALE AND FEMALE
CONNECTORS
To pull apart the connectors, pull on the connector itself, not
the wire harness.
HINT : C h e c k t o s e e w h a t k i n d o f connector you are
disconnecting before pulling apart.
Page 4026 of 4592
*The titles given inside the components are the names of the terminals (terminal codes) and are not treated as being
abbreviations.
ABBREVIATIONS D
ABBREVIATIONS
The following abbreviations are used in this manual.
ABS = Anti±Lock Brake System
A/C = Air Conditioning
A/T = Automatic Transaxle
COMB. = Combination
ECU = Electronic Control Unit
EGR = Exhaust Gas Recirculation
ESA = Electronic Spark Advance
EVAP = Evaporative Emission
FL = Fusible Link
IAC = Idle Air Control
J/B = Junction Block
LH = Left±Hand
O/D = Overdrive
R/B = Relay Block
RH = Right±Hand
SFI = Sequential Multiport Fuel Injection
SRS = Supplemental Restraint System
SW = Switch
TEMP. = Temperature
VSV = Vacuum Switching Valve
w/ = With
w/o = Without
Page 4028 of 4592

E
RELAY
Basically, an electrically operated
switch which may be normally
closed (1) or open (2).
Current flow through a small coil
creates a magnetic field which either
opens or closes an attached switch.
1. NORMALLY
CLOSED
2. NORMALLY
OPEN
SWITCH, MANUAL
Opens and closes
iitth b
SPEAKER
An electromechanical device which
creates sound waves from current
flow.
RELAY, DOUBLE THROW
A relay which passes current
through one set of contacts or the
other.
circuits, thereby
stopping (1) or
allowing (2) current
flow.1. NORMALLY
OPEN
2. NORMALLY
CLOSED
RESISTOR
An electrical component with a fixed
resistance, placed in a circuit to
reduce voltage to a specific value.SWITCH, DOUBLE THROW
A switch which continuously passes
current through one set of contacts
or the other.
RESISTOR, TAPPED
A resistor which supplies two or
more different non adjustable
resistance values.SWITCH, IGNITION
A key operated switch with several
positions which allows various
circuits, particularly the primary
ignition circuit, to become
operational.
RESISTOR, VARIABLE or RHEOSTAT
A controllable resistor with a variable
rate of resistance.
Also called a potentiometer or
rheostat.
SENSOR (Thermistor)
A resistor which varies its resistance
with temperature.SWITCH, WIPER PARK
Automatically returns wipers to the
stop position when the wiper switch
is turned off.
(Reed Switch Type)
SENSOR, SPEED
Uses magnetic impulses to open
and close a switch to create a signal
for activation of other components.TRANSISTOR
A solidstate device typically used as
an electronic relay; stops or passes
current depending on the voltage
applied at ºbaseº.
SHORT PIN
Used to provide an unbroken
connection within a junction block.WIRES
Wires are always drawn as
straight lines on wiring
diagrams.
Crossed wires (1) without a
black dot at the junction are
tj i d
(1) NOT
CONNECTED
SOLENOID
An electromagnetic coil which forms
a magnetic field when current flows,
to move a plunger, etc.
j
not joined;
crossed wires (2) with a
black dot or octagonal ( )
mark at the junction are
spliced (joined)
connections.
(2) SPLICED
Page 4029 of 4592
F RELAY LOCATIONS
[Engine Compartment]
[Instrument Panel]
Page 4031 of 4592