ECU TOYOTA CAMRY V20 1986 Service Information

wShort circuit in wire harness between ECU±IG
fuse and terminal 3 of main switch.
wInspect main switch.
(See page
BE±89)
INSPECT SWITCH OPERATION
Is there battery voltage between terminal 4 and
body ground with main switch turned on ? INSPECT POWER SOURCE
Is there battery voltage between terminal 3 and
body ground?
INSPECT INDICATOR LIGHT OPERATION
Connect terminal i to body ground. Does indicator light
light with main switch turned on?
wOpen circuit in wire harness between terminal 5
of main switch and body ground.
wBody ground faulty.
INSPECT GROUND CONNECTION
Is there continuity between terminal 5 and
body ground?
Is there battery voltage between terminal 4 and body
ground with main switch turned off?Open circuit in wire harness between ECU±IG fuse and
terminal 3 of main switch.
INSPECTION OF POWER SOURCE CIRCUIT
No
CONTINUED ON PAGE BE±75 Does indicator light light with main switch turned off?Inspect main switch.
(See page BE±89) Inspect main switch.
(See page BE±89)
Inspect main switch.
(See page BE±89)
Inspect main switch.
(See page BE±89) Replace fuse.
Is operation normal? Turn ignition switch on.
Is ECU±IG fuse normal?
MAIN SWITCHFuse faulty
Ye s Ye s
Ye s Ye s
Ye s
Ye s
Ye s
Ye s
± BODY ELECTRICAL SYSTEMCruise Control SystemBE±74

ASSEMBLY OF CYLINDER
(See page BR±18)
1. APPLY LITHIUM SOAP BASE GLYCOL GREASE TO
PARTS INDICATED WITH ARROWS
4. INSTALL DUST BOOTS AND SLIDING BUSHING
(a) Install the dust boots into the brake cylinder.
(b) Insure that the boot is secured firmly to the brake cyl-
inder groove.
(c) Install the bushing into the boots.
(d) Insure that the boot is secured firmly to the bushing
groove. 3. INSTALL CYLINDER BOOT AND SET RING IN
CYLINDER 2. INSTALL PISTON SEAL AND PISTON IN CYLINDER
± BRAKE SYSTEMFront BrakeBR±24

ASSEMBLY OF CYLINDER
(See page BR±34)
1. APPLY LITHIUM SOAP BASE GLYCOL GREASE TO
FOLLOWING PARTS:
(a) Main pin boot
(b) Sliding bushing and dust boots
(e) Piston, piston seal and cylinder boot
5. INSTALL SLIDING BUSHING AND DUST BOOTS
(a) Install the sliding bushing and dust boots into the
brake cylinder.
(b) Insure that the boots are secured firmly to the brake
cylinder groove. 3. INSTALL CYLINDER BOOT AND SET RING IN
CYLINDER
4. INSTALL MAIN PIN BOOT
Install the main pin boot in place. 2. INSTALL PISTON SEAL AND PISTON IN CYLINDER
± BRAKE SYSTEMRear BrakeBR±40

2. INSPECT SYSTEM CIRCUIT WITH CONNECTOR
DISCONNECTED
(a) Disconnect the connectors from the computer, in-
spect at the wire harness side connector.
If the circuit is not as specified, check and repair or re-
place the trouble part shown in the table above.
(b) Connect the connectors, and install the comput-
er cover.
Ignition switch off and brake pedal depressed
Engine running and PKB lever returned Ignition switch off and brake pedal returned
Ignition switch on and PKB lever pulled
Parking broke switch,
level warning switchStop light switch,
stop light Voltage or
Resistance Value
Check connector,
wiring harness
Front RH speed
sensor
FrontrH speed
sensor Ts connector,
wiring harness
Rear RH speed
sensor
Rear RH speed
sensor
Rear LH speed
sensorRear LH speed
sensor Ts connector shorted
Ignition switch offIgnition switch off
Ignition switch off
Ignition switch off Ignition switch off Tester Connection
Ignition switch offIgnition switch off
Ignition switch off
Ignition switch off Ignition switch off Ignition switch off
Ignition switch offIgnition switch off
Ignition switch onBattery voltage
No continuity
Battery voltage
0.85 ± 1.30 k fl
0.85± 1.30k
Battery voltage
Wiring harnessWiring harness
Wiring harness Battery voltage
0.85 ± 1.50 k
0.85 ± 1.50 k

No continuityNo continuity
No continuityNo continuityNo continuityTrouble Part
65±100

ECU±IG fuse Chrak Item
50±80

About 6
ContinuityResistance
Resistance
About 5
ResistanceAbout 6 0
Resistance
ResistanceAbout 6

ResistanceContinuity Resistance
Resistance
ResistanceContinuity
ResistanceAbout 6

ResistanceContinuity
Continuity
Continuity
ContinuityContinuity Continuity
Continuity Continuity
About 0 v
Continuity Continuity
Continuity
Continuity
FOG fuse Condition
ActuatorActuator
Actuator Voltage
VoltageVortege
Actuator Voltage
± BRAKE SYSTEMAnti±lock Brake System (A.B.S.)BR±103

(c) AS shown in the illustration, mount SST (C) in a vise,
and install the alternator to SST (C).
(d) To loosen the pulley nut turn SST (A) in the direction
shown in the illustration.
NOTICE: To prevent damage to the rotor shaft, do not
loosen the pulley nut more than one±half of a turn.
(e) Remove the alternator from SST (C).
(f) Turn SST (B) and remove SST (A and B).
(g) Remove the pulley nut and pulley.
INSPECTION AND REPAIR OF
ALTERNATOR
Rotor
1. INSPECT ROTOR FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between the slip
rings.
Standard resistance (Cold): 2.8 ± 3.0W
If there is no continuity replace the rotor.4. REMOVE PULLEY
(a) Hold SST(A) with a torque wrench, and tighten SST (B)
clockwise to the specified torque.
SST 09820±63010
Torque: 400 kg±cm (29 ft±Ib, 39 N±m)
(b) Check that SST (A) is secured to the rotor shaft.
(b) Using SST, remove the rectifier end frame.
SST 09286±46011
6. REMOVE ROTOR FROM DRIVE END FRAME5. REMOVE RECTIFIER END FRAME
(a) Remove the four nuts.
± CHARGING SYSTEMAlternatorCH±8

ASSEMBLY OF ALTERNATOR
(See page CH±6)
1. INSTALL ROTOR TO DRIVE END FRAME
2. ASSEMBLE DRIVE END FRAME AND RECTIFIER END
FRAME
(a) Using a plastic±faced hammer, lightly tap in the end frame.
(b) Install the four nuts.
3. INSTALL PULLEY
(a) Install the pulley to the rotor shaft by tightening the
pulley nut by hand.
(b) Hold SST(A)with a torque wrench, and tighten SST (B) clock-
wise to the specified torque.
SST 09820±63010
Torque: 400 kg±cm (29 ft±Ib, 39 N±m)
(c) Check that SST (A) is secured to the pulley shaft.
(d) As shown in the illustration, mount SST (C) in a vise, and
install the alternator to SST (C).
(e) To torque the pulley nut turn SST (A) in the direction
shown in the illustration.
Torque: 1,125 kg±cm (81 ft±Ib, 110 N±m )
(f) Remove the alternator from SST (C).
(g) Turn SST (6) and remove SST (A and6). 4. IF NECESSARY, REPLACE REAR BEARING
(a) Using SST, remove the bearing cover and bearing.
SST 09820±00021
NOTICE: Be careful not to damage the fan.
(b) Using SST and a press, press in a new bearing and
bearing cover.
SST 09285±76010
± CHARGING SYSTEMAlternatorCH±12

INSPECTION OF MASTER CYLINDER
HINT: Clean the disassembled parts with compressed air.
1. INSPECT MASTER CYLINDER BORE FOR SCORING
OR CORROSION
If a problem is found, clean or replace the cylinder.
2. INSPECT PISTON AND CUPS FOR WEAR, SCORING,
CRACKS OR SWELLING
If either one requires replacement, use the parts from the
cylinder kit.
3. INSPECT PUSH ROD FOR WEAR OR DAMAGE
If necessary, replace the push rod.
ASSEMBLY OF MASTER CYLINDER
(See page CL±5)
1. COAT PARTS WITH LITHIUM SOAP BASE GLYCOL
GREASE, AS SHOWN
2. INSERT PISTON INTO CYLINDER
3. INSTALL PUSH ROD ASSEMBLY WITH SNAP RING
4. INSTALL RESERVOIR TANK
Torque: 250 kg±cm (18 ft±Ib. 25 N±m)
INSTALLATION OF MASTER CYLINDER
(See page CL±5)
1. INSTALL MASTER CYLINDER WITH MOUNTING NUTS
2. CONNECT CLUTCH LINE TUBE
3. CONNECT CLEVIS, AND INSTALL CLEVIS PIN AND
CLIP
Secure the clevis pin with the clip.
4. FILL CLUTCH RESERVOIR WITH BRAKE FLUID AND
BLEED CLUTCH SYSTEM (See page CL±4)
5. CHECK FOR LEAKS
6. CHECK AND ADJUST CLUTCH PEDAL
(See page CL±3)
7. INSTALL INSTRUMENT LOWER FINISH PANEL
Connect the air duct to the instrument lower finish panel and install
the instrument lower panel. 3. REMOVE PISTON
Using compressed air, remove the piston from the cylinder.
± CLUTCHClutch Master CylinderCL±6

ON±VEHICLE INSPECTION
Low Temperature (Below 85
°C (185°F))
1. TURN IGNITION SWITCH ºONº
Check that the fans stop.
If not, check the cooling fan relays and water temperature
sensor, and check for a separated connector or severed wire
between the cooling fan relay and water temperature
sensor.
2. DISCONNECT WATER TEMPERATURE SENSOR
CONNECTOR
Check that the fans rotate.
If not, check the cooling fan relays, fan motor, engine main
relay and fuse, and check for a short circuit between the
cooling fan relay and water temperature sensor.
3. CONNECT WATER TEMPERATURE SENSOR
CONNECTOR
INSPECTION OF ELECTRIC COOLANT
FAN COMPONENTS
1. INSPECT COOLING FAN ECC FOR CIRCUIT
Disconnect the cooling fan ECU, and check the connec-
tor on the wiring harness side as shown in the chart on the
next page.
High Temperature (85 ± 90°C (185±194°F))
4. START ENGINE
(a) Raise coolant temperature to 85 ± 90°C (185 ±194°F).
(b) Check that the fans rotate. (at low speed)
If not, replace the water temperature sensor.
High Temperature (Above 90°C (194°F))
5. START ENGINE
(a) Raise coolant temperature to above 90
°C (194°F).
(b) Check that the fans rotate. (at high speed)
If not, replace the water temperature sensor.
± COOLING SYSTEMElectric Cooling Fans (2VZ±FE)CO±24

The ER system is composed of there basic sub±systems: Fuel, Air Induction and Electronic Control Systems.
FUEL SYSTEM
Fuel is supplied under constant pressure to the EFI injectors by an electric fuel pump. The injectors inject a
metered quantity of fuel into the intake manifold in a accordance with signals from the ECU (Electronic Control
Unit).
AIR INDUCTION SYSTEM
The air induction system provides sufficient air for engine operation.
ELECTRONIC CONTROL SYSTEM
The Camry 3S±FE and 2V1±FE engines are equipped with a Toyota Computer Control System (TCCS) which
centrally controls the EFI, ESA, ISC, Diagnosis systems etc. by means of an Electronic Control Unit (ECU±
formerly ER computer) employing a microcomputer.
By means of the ECU, the TCCS controls the following functions:
1. Electronic Fuel Injection (EFI)
The ECU receives signals from various sensors indicating changing engine operation conditions such as:
Intake air volume
Intake air temperature
Coolant temperature
Engine rpm
Acceleration/deceleration
Exhaust oxygen content etc.
The signals are utilized by the ECU to determine the injection duration necessary for an optimum air±fuel ratio.
2. Electronic Spark Advance (ESA)
The ECU is programmed with data for optimum ignition timing under any and all operating conditions.
Using data provided by sensors which monitor various engine functions (rpm, coolant temperature, etc.), the
microcomputer (ECU) triggers the spark at precisely the right instant. (See IG section)
3. Idle Speed Control (ISC)
The ECU is programmed with target idling speed values to respond to different engine conditions (coolant
temperature, air conditioner ON/OFF, etc.). Sensors transmit signals to the ECU which control the flow of air
through the by±pass of the throttle valve and adjust idle speed to the target value. (See page FI±45,115
or 62, 117)
4. Diagnosis
The ECU detects any malfunctions or abnormalities in the sensor network and lights a ºCHECKº engine warn-
ing light on the instrument panel. At the same time, the trouble is identified and a diagnosis code is recorded
by the ECU. The diagnosis code can be read by the number of blinks of the ºCHECKº engine warning light
when terminals TE1 and E1 are connected. The diagnostic codes are refer to the later page.
(See page FI±25 or 27)
5. Fail±safe Function
In the event of the sensor malfunctioning, a back±up circuit will take over to provide minimal drivability, and
the ºCHECKº engine warning light.
± EFI SYSTEMSystem DescriptionFI±4

PRECAUTIONS
1. Before working the fuel system, disconnect the cable
from negative (±) terminal of the battery.
HINT: Any diagnostic code retained by the computer will be erased
when the battery terminal is removed. Therefore, if necessary, read
the diagnosis before removing the battery terminal.
2. Do not smoke or work open flame when working the fuel system.
3. Keep gasoline off rubber or leather parts.
INSPECTION PRECAUTIONS
MAINTENANCE PRECAUTIONS
1. CHECK CORRECT ENGINE TUNE±UP
(See page EM±8)
2. PRECAUTIONS WHEN CONNECTING GAUGE
(a) Use the battery as the power source for the timing light, tachome-
ter, etc.
(b) (3S±FE)
Connect the test probe of a tachometer to the service
connector of the distributor.
(c) (2VZ±FE)
Connect the test probe of a tachometer to the terminal
IG ± of the check connector.
3. IN EVENT OF ENGINE MISFIRE FOLLOWING
PRECAUTIONS SHOULD BE TAKEN
(a) Check proper connection of battery terminals, etc.
(b) Handle high±tension cords carefully.
(c) After repair work, check that the ignition coil terminals and
all other ignition system lines are reconnected securely.
(d) When cleaning the engine compartment, be especially
careful to protect the electrical system from water.
4. PRECAUTIONS WHEN HANDLING OXYGEN
SENSOR(S)
(a) Do not allow the oxygen sensor to drop or hit against an ob-
ject.
(b) Do not allow the sensor to come into contact with water.
± EFI SYSTEMPrecautionsFI±5