ignition TOYOTA CAMRY V20 1986 Service Information

INSPECTION ELECTRONIC CONTROL
COMPONENTS
1. INSPECT VOLTAGE OF ECT ECU CONNECTOR
(a) Remove the glove box and instrument panel.
(b) Turn on the ignition switch.
(e) Measure the voltage at each terminal.
Throttle valve fully closed to fully open Throttle valve fully closed to fully open
Throttle valve fully closed to fully open
Vehicle moving (Cruise control OFF)Standing still (Cruise control OFF) Throttle valve opening above 1 .5°
When brake pedal is not depressed When brake pedal is depressed Throttle valve fully closed Throttle valve fully closed
Throttle valve fully closed
Throttle valve fully closed Throttle valve fully open Throttle valve fully open Throttle valve fully openMeasuring condition
Except L range
Except N range Except 2 rangeVoltage (V)
Terminal
N range 2 range
L range
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±32

2. INSPECT SOLENOID
(a) Disconnect the connector from the ECT computer.
(b) Measure the resistance between S1, S2, SL and
ground.
Resistance: 11 ± 15


(c) Apply battery voltage to the solenoid. Check that an
operation noise can be heard from the solenoid.
HINT: If there is foreign matter in the solenoid valve,
there will be no fluid control even with solenoid opera-
tion.
3. CHECK SOLENOID SEALS
If there is foreign material in the solenoid valve, there
will be no fluid control even with solenoid operation.
(a) Check No. 1 and No. 2 solenoid valves.
wApplying 5 kg/cm2 (71 psi, 490 kPa) or compressed
air, check that the solenoid valves do not leak the air.
wWhen supply battery voltage to the solenoids,
check that the solenoid valves open.
(b) Check the lock±up solenoid valve.
wApplying 5 kglcm2 (71 psi, 490 kPa) of com-
pressed air, check that the solenoid valve
opens.
wWhen supply battery voltage to the solenoid,
check that the solenoid valve does not leak the
air.
Coolant temp. above 122°F (50°C) Coolant temp. below 122°F (50°C)
O/D main switch turned OFF O/D main switch turned ONMeasuring condition
Ignition switch ON
Vehicle movingStanding still
PWR pattern
NORM patternVoltage (V)
Terminal
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±33

Diagnosis System
DESCRIPTION
1. A self±diagnosis function is. built into the electrical control
system. Warning is indicated by the overdrive OFF indicator.
HINT: Warning and diagnostic codes can be read only when
the overdrive switch is ON. If OFF, the overdrive OFF
indicator is lit continuously and will not blink.
(a) If a malfunction occurs within the speed sensors or sole-
noids, the overdrive OFF light will blink to warn the driver.
However, there will be no warning of a malfunction with
lock±up solenoid.
W The diagnostic code can be read by the number of
blinks of the overdrive OFF indicator when terminals
Tt and E1 are short±circuited. (See page AT± 191)
(c) The throttle position sensor or brake signal are not indicated,
but inspection can be made by checking the voltage at ter-
minal Tt of the check connector.
(d) The signals to each gear can be checked by measuring the
voltage at terminal Tt of the check connector while driving.
2. The diagnostic (malfunction) code is retained in memory by the
ECU and due to back±up voltage, is not canceled out when the
engine is turned off. Consequently, after repair, it is necessary
to turn the ignition switch off and remove the fuse EFI (15A)
(A540E) or DOME (20A)
(A540H) or disconnect the Engine and ECT ECU (A540E)
or ECT ECU (A540H) connector to cancel out the diagnostic
(malfunction) code. (See page AT±192)
HINT:
wLow battery voltage will cause faulty operation of the diag-
nosis system. Therefore, always check the battery first.
wUse a voltmeter and ohmmeter that have an impedance of
at least 10 k
/V.
CHECK O/D OFF INDICATOR LIGHT
1. Turn the ignition switch ON.
2. The O/D OFF light will come on when the O/D switch
placed at OFF.
3. When the O/D switch is set to ON, the O/D OFF light should go
out.
If the O/D OFF light flashes when the O/D switch is set to
ON, the electronic control system is faulty.
± AUTOMATIC TRANSAXLETroubleshooting (Diagnosis System) (A540E and A540H)AT±190

wn the event of a malfunction, the light will blink once
every 0.5 seconds. The number of blinks will equal
the first number and, after 1.5 seconds pause, the
second number of the two digit diagnostic code. If
there are two or more codes, there will be a 2.5 sec-
onds pause between each.
HINT: In the event of several trouble codes occurring
simultaneously, indication will begin from the smaller
value and continue to the larger.
4. REMOVE SST
SST 09843±18020
READ DIAGNOSTIC CODE
1. TURN IGNITION SWITCH AND O/D SWITCH TO ON
Do not start the engine.
HINT: Warning and diagnostic codes can be read only
when the overdrive switch is ON. If OFF, the overdrive OFF
light will light continuously and will not blink.
2. SHORT Tt TERMINAL CIRCUIT OF CHECK
CONNECTOR
Using SST, short terminals Tt and E1 of the check connector.
SST 09843±18020
3. READ DIAGNOSTIC CODE
Read the diagnostic code as indicated by the number of
times the O/D OFF light flashes.
(Diagnostic Code Indication)
wIf the system is operating normally, the light will blink
once every 0.25 seconds.
± AUTOMATIC TRANSAXLETroubleshooting (Diagnosis System) (A540E and A540H)AT±191

CANCEL OUT DIAGNOSTIC CODE
1. After repair of the trouble area, the diagnostic code
retained in memory by the Engine and ECT ECU (A540E)
or ECT ECU (A540H) must be canceled by removing the fuse EFI
(15A) (A540E) or DOME (20A) (A540H) for 10
seconds or more, depending on ambient temperature (the
lower the temperature, the longer the fuse must be left
out with the ignition switch OFF.
wHINT:Cancellation can be also done by removing the battery
negative (±) terminal, but in this case other memory systems
(engine control system diagnosis memory,
clock. ETR, etc.) will also be canceled out
wThe diagnostic code can be also canceled out by disconnect-
ing the Engine and ECT ECU (A540E) or ECT
ECU (A540H) connector.
wIf the diagnostic code is not canceled out, it will be retained
by the Engine and ECT ECU (A540E) or ECT
ECU (A540H) and appear along with a new code in
event of future trouble.
2. After cancellation, perform a road test to confirm that a
ºnormal codeº is now read on the O/D OFF indicator.
± AUTOMATIC TRANSAXLETroubleshooting (Diagnosis System) (A540E and A540H)AT±193

3. INSPECT EACH UP±SHIFT POSITION
(a) Warm up the engine.
Coolant temperature: 176
°F (80°)
(b) Turn the O/D switch to ºONº.
(c) Place the pattern select switch in ºNormalº and the shift
lever into the D range.
(d) During a road test (above 10 km/h or 6 mph) check that volt-
age at the Tt terminal is as indicated below for each up±
shift position.
If the voltage rises from 0V to 7V in the sequence shown,
the control system is okay.
The chart on the left shows the voltmeter reading and cor-
responding gears.
HINT: Determine the gear position by a fight shock or
change in engine rpm when shifting. The lock±up clutch will
turn ON only infrequently during normal 2nd and 3rd gear
operation. To trigger this action, press the accelerator pedal
to 50% or more of its stroke. At less than 50%, the voltage
may change in the sequence 2v ± 4V ± 6V ± 7V. 2. INSPECT BRAKE SIGNAL
(a) Depress the accelerator pedal until the Tt terminal indi-
cates 8V.
(b) Depress the brake pedal and check the voltage read-
ing from the Tt terminal.
Brake pedal depressed ...... 0V
Brake pedal released . . . . . . . . 8V
If not as indicated, there is a malfunction in either the
stop light switch or circuit.
INSPECTION OF ECT OR Tt TERMINAL
VOLTAGE
1. INSPECT THROTTLE POSITION SENSOR SIGNAL
(a) Turn the ignition switch to ON. Do not start the engine.
(b) Connect a voltmeter to terminals Tt and E1.
(c)while slowly depressing the accelerator pedal, check
that Tt terminal voltage rises in sequence.
If the voltage does not change in proportion to the
throttle opening angle, there is a malfunction in the
throttle position sensor or circuit.
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±215

INSPECTION OF ELECTRONIC CONTROL
COMPONENTS
1. (A540E)
INSPECT VOLTAGE OF TCCS ECU CONNECTOR
(a) Turn on the ignition switch.
(b) Measure the voltage at each terminal.
Coolant temp. 176°F (84°C)
Cruise control main
switch OFFO/D main switch turned OFF O/D main switch turned ON Throttle valve fully closed
Throttle valve fully closed Brake pedal is depressed
Throttle valve fully openMeasuring condition
Brake pedal is released
Throttle valve open
Vehicle movingVehicle moving P, R or N range D, 2 or L range
Standing stillStanding still NORM patternVoltage (V)
PWR pattern Terminal
± AUTOMATIC TRANSAXLE(A540E and A540H)AT±216

2. (A540H)
INSPECT VOLTAGE OF ECT ECU CONNECTOR
(a) Turn on the ignition switch.
(b) Measure the voltage at each terminal.
Throttle valve fully closed to fully open
Throttle valve fully closed to fully openThrottle valve fully closedMeasuring conditionMeasuring condition
Throttle valve openExcept N rangeExcept R range
Except 2 range
Except L range
Voltage (V)Voltage IV1
R range Terminal
Terminal2 range N range
L range
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±217

INSPECTION OF ELECTRIC CONTROL
COMPONENTS
1. INSPECT SHIFT LOCK CONTROL COMPUTER
Using a voltmeter, measure the voltage at each termi-
nals.
HINT: Do not disconnect the computer connector.
2. INSPECT SHIFT LOCK SOLENOID
(a) Disconnect the solenoid connector.
(b) Using an ohmmeter, measure the resistance be-
tween terminals.
Standard resistance: 21 ± 27


(c) Apply the battery voltage between terminals.
Check that an operation noise can be heard
from the solenoid.
Ignition switch 4N, P range and depress brake pedal Ignition switch ACC position and except P range
Shift except P range under conditions above
Shift except P range under condition above Ignition switch ACC position and P range
Ignition switch ACC position and P range Ignition switch ON position and P range Ignition switch ACC position
(Approx.±after 20 seconds) Ignition switch ON position
(Approx.±after one second) Depress brake pedalMeasuring condition
Depress brake pedal
Except P rangeVoltage (V)
ConnectorTerminal
± AUTOMATIC TRANSAXLEShift Lock SystemAT±410

NOTICE:
1. Turn off all electrical components and the ignition
switch before replacing a fuse or fusible link. Do not
exceed the fuse or fusible link amperage rating.
2. Always use a fuse puller for removing and inserting
a fuse. Remove and insert straight in and out without
twisting. Twisting could force open the terminals too
much, resulting in a bad connection.
If a fuse or fusible link continues to blow, a short circuit is
indicated. The system must be checked by a qualified tech-
nician.
± BODY ELECTRICAL SYSTEMGeneral informationBE±4