cruise control TOYOTA CAMRY V20 1986 Service Information

2. Electronic Control System
COMPONENTS
The electronic control system for controlling the shift timing and the operation of the lock±up clutch
is composed of the following three parts:
(a) Sensors: These sense the vehicle speed and throttle position and send this data to the ECT ECU
in the form of electronic signals.
(b) ECT ECU: This determines the shift and lock±up timing based upon the signals from the. sensors.
(e) Actuators: Solenoid valves divert hydraulic pressure from one circuit of the hydraulic control unit
to another, thus controlling shifting and lock±up timing.
VEHICLE SPEED SENSOR
NO. 1 AND NO. 2
BRAKE LIGHT SWITCH
O/D MAIN SWITCH
THROTTLE POSITION
SENSOR
CRUISE CONTROL
COMPUTER PATTERN SELECT
SWITCH
NEUTRAL START
SWITCH
LOCK±UP SOLE±
NOID VALVE NO. 2 SOLENOID
VA LV E NO. 1 SOLENOID
VA LV E
Control of shift
tinning
Self±diagnostic
systemControl of lock±up
timing
WATER TEMP.
SENSORO/D OFF INDI±
CATOR LIGHT Back±up system
ECT ECU
ENGINE
ECU
ACTUATOR
SENSOR ACTUATOR
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±10

Is voltage between terminals OD2 and GND as fol-
lows?
O/D switch turn ON: 10 ± 14V
O/D switch turn OFF: 0VRoad test while shifting manually with ECT
ECU connector disconnected.
Is there overdrive up±shift in the D range when
shifting from L to 2 to D?
Is voltage between terminals OD, and GND as fol-
lows?
Approx. 5 V
Is voltage between ECT ECU terminals
OD, and GND normal with the cruise control com-
puter connector pulled out?Connect ECT ECU connector, and while driving
does ECT terminal voltage rise from
0V to 7V in sequence?
No up±shift to overdrive (After warm±up)
Are there battery voltage between
ECT ECU terminals L and GND
when in the D range?Are there battery voltage between
ECT ECU terminals 2 and
GND when in the D range?
wFaulty neutral start switch circuit
wFaulty neutral start switch
Faulty ECT ECU
Faulty cruise control wire harnessFaulty O/D switch harness
Faulty O/D switch
Faulty cruise control computer±Faulty transaxle
Faulty solenoid
Try another ECT ECU
Try another ECT ECUFaulty transaxle
Trouble No. 3
Ye sYe s
Ye s
Ye sYe sYe s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±29

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

ROAD TEST (A140E)
NOTICE: Perform the test at normal operating fluid
temperature (122 ± 176°F or 50 ± 84°C). .
1. D RANGE TEST IN NORM AND PWR PATTERN
RANGES
Shift into the D range and hold the accelerator pedal
constant at the full throttle valve opening position.
Check the following:
(a) 1±2, 2±3 and 3±O/D up±shifts should take place, and
shift points should conform to those shown in the au-
tomatic shift schedule. (See page AT±49)
Conduct a test under both Normal and Power patterns.
HINT:
There is no O/D up±shift when coolant temperature is
below 122
°F (50°C).
There is no lock±up when the vehicle speed is 10 km/h (6
mph) less than the set cruise control speed.
EVALUATION
(1) If there is no 1 ± 2 up±shift:
wNo. 2 solenoid is stuck
w1±2 shift valve is stuck
(2) If there is no 2 ± 3 up±shift:
w No. 1 solenoid is stuck
w2±3 shift valve is stuck
(3) If there is no 3 ± O/D up±shift:
w3±O/D shift valve is stuck
(4) If the shift point is defective:
wThrottle valve, 1±2 shift valve, 2±3 .shift valve, 3±
wO/D shift valve etc., are defective
(5) If the lock±up is defective:
wLock±up solenoid is stuck
wLock±up relay valve is stuck
(b) In the same manner, check the shock and slip at the 1
±2, 2 ± 3 and 3 ± O/D up±shifts.
EVALUATION
If the shock is excessive:
wLine pressure is too high
wAccumulator is defective
wCheck ball is defective
(c) Run at the D range lock±up or O/D gear and check for
abnormal noise and vibration.
HINT: The check for the cause of abnormal noise and
vibration must be make with extreme care as it could
also be due to loss of balance in the drive shaft, tire,
torque converter, etc.
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A140L and
A140E)AT±43

Is voltage between terminals OD2 and GND as fol-
lows?
O/D switch turn ON: 10 ± 14V
O/D switch turn OFF: 0VRoad test while shifting manually with solenoid
wire connector disconnected.
Is there overdrive up±shift in the D range
when shifting from L to 2 to D
Is voltage between Engine and ECT ECU
terminals OD, and E1 normal with the cruise con-
trol computer connector pulled out?Connect solenoid wire connector, and while driv-
ing does Tt terminal voltage rise from
0V to 7V in sequence?
Is voltage between terminals OD, and E, as fol-
lows?
Approx. 5 VAre there 10 ± 14V between Engine and
ECT ECU terminals L and E1 when in the D
range?
No up±shift to overdrive (After warm±up)
Are there 10 ± 14V between
Engine and ECT ECU terminals 2
and E1 when in the D range?
w Faulty Engine and ECT ECU
wFaulty cruise control wire harnessFaulty neutral start switch circuit
Faulty neutral start switch
Faulty O/D switch harness
Faulty O/D switch Try another Engine and ECT ECU
Try another Engine and ECT ECU
Faulty cruise control computerFaulty transaxle
Faulty solenoid Faulty transaxle
Trouble No. 3
Y
es
Ye s
Ye sYe s
Ye s Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±209

Disconnect the cruise control computer connector.
Is voltage between terminals 4D1 and GND
as follows?
Approx. 5VIs voltage between terminals OD2 and GND as fol-
lows?
O/D switch turn ON: 10 ± 14V
O/D switch turn OFF: 0VRoad test while shifting manually with solenoid
wire connector disconnected.
Is there overdrive up±shift in the D range when
shifting from L to 2 to D?
Is voltage between terminals OD1 and GND as
follows?
Approx. 5VConnect solenoid wire connector, and while driv-
ing does Tt terminal voltage rise from OV
to 7 V i n sequence?
Faulty ECT ECU
(Short circuit in ECT wire harness or EFI
water temp. sensor bad)Are there 10 ± 14V between ECT
ECU terminals LL and GND when in the
D range?
No up±shift to overdrive (After warm±up)
Are there 10 ± 14V between ECT
ECU terminals 2L and GND when in
the D range?
wFaulty neutral start switch circuit
wFaulty neutral start switch
wFaulty O/D switch circuit
wFaulty O/D switch
Faulty cruise control computerFaulty transaxle
Faulty solenoid
Try another ECT ECU Try another ECT ECUFaulty transaxle
Trouble No. 3
Ye sYe s
Ye s
Ye sYe s Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±213

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

Light Control Rheostat
TAIL Fuse
IGN Fuse
Water Temperature Sender Gauge
Ground
Seat Beh Warning Relay
Brake Fluid Level Warning Switch and Parking
Brake Switch
CHARGE Fuse
TCCS ECU
A.B.S. ECU
Cruise Control ECU and ECT ECU
Ground
Fuel Sender Gauge Terminal 3
Fuel Sender Gauge Terminal 2
GAUGE Fuse
DOME Fuse
Door Courtesy Switch
Low Oil Pressure Switch
Light Failure Sensor
Combination Meter and Gauges
(w/o Tachometer)
Turn Signal Switch Terminal 28
Ground
Turn Signal Switch Terminal 25
Turn Signal Switch Terminal 23 (USA)
HEAD±HI (RH) Fuse (CANADA)
A/T Oil Temperature Switch
COMBINATION METER CIRCUIT
Wiring Connector Side
No.
± BODY ELECTRICAL SYSTEMCombination MeterBE±32

Light Control Rheostat
TAIL Fuse
IGN Fuse
Water Temperature Sender Gauge
Ground
Seat Belt Warning Relay
Brake Fluid Level Warning Switch and Parking
Brake Switch
CHARGE Fuse
TCCS ECU ,
A. B. S. ECU
Cruise Control ECU and ECT ECU
Ground
Fuel Sender Gauge Terminal 3
Fuel Sender Gauge Terminal 2
. GAUGE Fuse
DOME Fuse
Door Courtesy Switch
Low Oil Pressure Switch
Light Failure Sensor
Turn Signal Switch Terminal 28
Ground
Turn Signal Switch Terminal 25
Turn Signal Switch Terminal 23 (USA)
HEAD±HI (RH) Fuse (CANADA)
A/T Oil Temperature Switch
Igniter
Combination Meter and Gauges
(w/ Tachometer)
COMBINATION METER CIRCUIT
Wiring Connector Side
No.
± BODY ELECTRICAL SYSTEMCombination MeterBE±33

CRUISE CONTROL SYSTEM
Wiring Diagram
± BODY ELECTRICAL SYSTEMCruise Control SystemBE±69