1986 TOYOTA CAMRY V20 check engine light

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

TROUBLESHOOTING FLOW±CHART (A540E)
HINT:
wIf diagnostic code Nos. 42, 61, 62 or 63 are output, the overdrive OFF indicator light will begin to
blink immediately to warn the driver. However, an impact or shock may cause the blinking to stop;
but the code will still be retained in the Engine and ECT ECU memory until canceled out.
wThere is no warning for diagnostic code No. 64.
wIn the event of a simultaneous malfunction of both No. 1 and No. 2 speed sensors, no diagnostic
code will appear and the fail±safe system will not function. However, when driving in the D range,
the transaxle will not up±shift from first gear, regardless of the vehicle speed.
Check continuity between Engine and ECT
ECU connector SP, terminal and body ground.
(See page AT±216)
Check continuity between Engine and ECT
ECU connector SP2 terminal and body ground.
(See page AT±216)
1. Diagnostic code 42 (No. 1 speed sensor circuitry)
Check wiring between Engine and ECT ECU
and No. 2 speed sensor. Check wiring between Engine and ECT ECU
and combination meter.
2. Diagnostic code 61 (No. 2 speed sensor circuitry)
Check No. 2 speed sensor.
(See page AT±234) Substitute another Engine and ECT ECU.
Substitute another Engine and ECT ECU.Repair or replace No. 1 speed sensor.
Repair or replace No. 2
speed sensor. Check No. 1 speed sensor.
± AUTOMATIC TRANSAXLETroubleshooting (Diagnosis System) (A540E and A540H)AT±194

S. INSPECT AND ADJUST THROTTLE CABLE
(a) Depress the accelerator pedal all the way and check that
the throttle valve opens fully.
HINT: If the valve does not open fully, adjust the accelera-
tor cable.
(b) Fully depress the accelerator pedal.
(c) Measure the distance between the end of the boot and
stopper on the cable.
Standard distance: 0 ± 1 mm (0 ± 0.04 in.)
If the distance is not standard, adjust the cable by the ad-
justing nuts.
7. INSPECT AND ADJUST SHIFT CABLE
When shifting the shift lever from the ±N position to other
positions, check that the lever can be shifted smoothly and
accurately to each position and that the position indicator
correctly indicates the position.
If the indicator is not aligned with the correct position, carry
out the following adjustment procedures.
(a) Loosen the swivel nut on manual shift lever.
(b) Push the manual lever fully toward the right side of the ve-
hicle.
(c) Return the lever two notches to NEUTRAL position.
(d) Set the shift lever to N.
(e) While holding the lever lightly toward the R range side,
tighten the swivel nut.
8. ADJUST NEUTRAL START SWITCH
If the engine will start with the shift selector in any range
other than N or P range, adjustment is required.
(a) Loosen the neutral start switch bolts and set the shift se-
lector to the N range.
(b) Align the groove and neutral basic line.
(c) Hold in position and tighten the bolts.
Torque: 55 kg±cm (48 in.±lb, 5.4 N±m)
9. INSPECT IDLE SPEED IN RANGE)
Idle speed: 700 rpm
± AUTOMATIC TRANSAXLETroubleshooting (Preliminary Check) (A540E and A540H)AT±201

2. 2 RANGE TEST
Shift into the 2 range and, while driving with the accel-
erator pedal held constantly at the full throttle valve
opening position, push in one of the pattern selectors
and check or the following points.
(a) Check to see that the 1 ± 2 up±shift takes place and
that the shift point conforms to it shown on the auto-
matic shift schedule. (See page AT±230)
(b) While running in the 2 range and 2nd gear, release
the accelerator pedal and check the engine braking ef-
fect.
EVALUATION
If there is no engine braking effect:
w Second coast brake is defective (f) Check for the lock±up mechanism.
(1) Drive in D range, O/D gear, at a steady speed
(lock±up ON) of about 75 km/h (47 mph).
(2) Lightly depress the accelerator pedal and check
that the engine rpm does not change abruptly.
If there is a big jump in engine rpm, there is no
lock±up. (d) While running in the D range, 2nd, 3rd and O/D
gears, check to see that the possible kick±
down vehicle speed limits for 2 ± 1, 3 ± 2 and
O/D ± 3 kickdowns conform to those indicated
on the automatic shift schedule. (See page
AT±230)
(e) Check for abnormal shock and slip at kick±down.
(c) Check for abnormal noise at acceleration an4
deceleration, and for shock at up±shift and
down shift.
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A540E and
A540H)AT±228

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

Current is led from the battery to terminal 12 of the running light relay.
Operation examples of the switch are shown below.
1. IGNITION SWITCH ºONº AND LIGHT CONTROL SWITCH ºOFFº
When the switches are set, current is led from the battery to terminal 1 of the running light relay. Also,
because continuity is made between terminal 3 and the body ground, and 5 and the body ground of
the running light relay, the taillight control relay and headlight control relay are turned on.
Then the taillights and headlights light up.
HINT: Because terminal 14 of the running light relay is not grounded at all times, the headlight dimmer
relay is off, so that the headlights light up at the low beam.
2. LIGHT CONTROL SWITCH IN ºHEADº
When the switch is set, continuity is made between terminal 4 and the body ground, and 2 and the body
ground of the running light relay. Also, because the continuity is made between terminal 5 and the body
ground, and 3 and the body ground of the running light relay at all times, the taillights and headlights
light up.
HINT: When the headlight dimmer switch is set to ºHIGHº, continuity is made between terminal 13 of
the running light relay and the body ground. Also, because continuity is made between terminal 14 of
the running light relay and the body ground, the headlight dimmer relay is turned on. Then the head-
lights go on at the high beam.
3. HEADLIGHT DIMMER SWITCH IN ºFLASHº
When the switch is set, continuity is made between terminal 6 and the body ground, and 13 and the
body ground of the running light relay. Also, because the continuity is made between terminal 5 and
the body ground, and 14 and the body ground of the running light relay, the headlights flash.
4. ENGINE STOPS (IGNITION SWITCH ºONº)
When the engine is stopped, because the continuity between terminal 5 and terminal 10 of the running
light relay remains, so the running lights also remain.
HINT: If ignition switch is turned to ºOFFº, running lights will go off because the continuity between termi-
nal 5 and terminal 10 of the running light relay is cut off.
Light Control Rheostat
INSPECTION OF RHEOSTAT
INSPECT RHEOSTAT OPERATION
(a) Connect the positive (+) lead from the battery to
terminal 1 and the negative (±) lead to terminal 2.
(b) Connect the terminals 1 and 3 through a 3.4 W test bulb.
(c) Gradually turn the rheostat knob from the bright side to
dark side, check that the test bulb brightness changes
from bright to dark.
If operation is not as specified, replace the rheostat.
Daytime Running Light System
(CANADA)
DESCRIPTION
± BODY ELECTRICAL SYSTEMLightingBE±23

(Relay Operation)
(a) Connect the positive (+) lead from the voltmeter to ter-
minal 7 and negative (±) lead to terminal 10.
(b) Check that there is battery voltage with light control
switch is turned on.
If operation is not as specified, replace the relay.If continuity is not as specified, replace the relay.
2. INSPECT DAYTIME RUNNING LIGHT RELAY
(Relay Circuit)
Disconnect the connector from the relay and inspect the
connector on the wire harness side as shown in the chart.
INSPECTION OF RELAY
1. INSPECT DIMMER RELAY (Continuity)
If circuit is as specified, inspect relay operation.
Apply battery voltage to
terminals 2 and 4.
Light control switch
position
Light control switch
position
Headlight dimmer
switch positionHeadlight dimmer
switch positionLow beam or High beam
Ignition switch
position 7 ± Ground
10 ± Ground
High beam or Flash 13 ± Ground
3 ± Ground
5 ± Ground
Tester connection
Ground terminal 5
Specified value
Battery voltageBattery voltageBattery voltage
Battery voltage Battery voltageNo continuity
No continuity TAIL or HEADNo continuity
No continuity
14 ± Ground12 ± GroundON or STARTLOCK or ACC
1 ± GroundOFF or TAIL
8 ± Ground2 ± Ground
6 ± Ground4 ± Ground
No voltage
No voltage
No voltageContinuity
Continuity Continuity
Continuity
ContinuityContinuity
Condition
Check for
Low beam Condition
Running
Terminal
Constant
Constant
Constant
Constant
Constant Voltage
EngineHEAD
Flash
StopOFF
± BODY ELECTRICAL SYSTEMLightingBE±25