warning light TOYOTA CAMRY V20 1986 Service Information

DIAGNOSIS SYSTEM
DESCRIPTION
The ECU contains a built±in, self±diagnosis system which de-
tects troubles within the engine signal network and then flashed
a
warning on the ºCHECKº engine warning light on the instrument
panel flashes.
By analyzing various signals shown in the tables (See pages FI±
25 or 27) the ECU detects system malfunctions which are re-
lated to the various operating parameter sensors or actuator.
The ECU
stores the failure code associated with the detected failure until
the diagnosis system is cleared by removing the EFI fuse with
the ignition switch OFF.
A ºCHECKº engine warning light on the instrument panel informs
the driver that a malfunction has been detected.
The light goes oft automatically when the malfunction has been
cleared.
OUTPUT OF DIAGNOSTIC CODES
To obtain an output of diagnostic codes, proceed as follow:
1. Initial conditions
(a) Battery voltage 11 V or more
(b) Throttle valve fully closed (throttle position sensor IDL
points closed)
(e) Transmission in neutral position
(d) Accessories switched OFF
(e) Engine at normal operating temperature
2. Turn the ignition switch to ON. Do not start the engine.
3. Using SST, connect terminals TE1 and E1 of the check con-
nector.
SST 09843±18020
ºCHECKº ENGINE WARNING LIGHT
CHECK
1. The ºCHECKº engine warning light will come on when the igni-
tion switch is placed at ON and the engine is not
running.
2. When the engine is started, the ºCHECKº engine warning light
should go off.
If the light remains on, the diagnosis system has detected a
malfunction or abnormality in the system.
± EFI SYSTEMDiagnosis SystemFI±22

(b) Malfunction Code Indication
wIn the event of a malfunction, the light will blink every 0.5
seconds. The first number of blinks will equal the first
digit of a 2±digit diagnostic code and, after a 1.5 second
pause, the 2nd number of blinks will equal the 2nd. If
there are two or more codes, there will be a 2.5 second
pause between each.
wAfter all the codes have been signalled there will be a
4.5 second pause and they will all be repeated as long
as the terminals TE1 and E1 of the check connector are
shorted.
HINT: In the event of a number of trouble codes, indica-
tion will begin from the smaller value and continue in
order to the larger. Diagnostic Codes (See page FI±25 or 27)
(a) Normal System Operation (no malfunction)
wThe tight will alternately blink ON and OFF 2 times per
second. 4. Read the diagnostic code as indicated by the number of
flashes of the ºCHECKº engine warning light.
5. After the diagnostic check, remove the SST.
SST 09843±18020
± EFI SYSTEMDiagnosis SystemFI±23

CANCELLING DIAGNOSTIC CODE
1. After repair of the trouble area, the diagnostic code retained
in memory by the ECU must be cancelled out by removing
the EFI fuse (15 A) 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.
HINT:
wCancellation can also be done by removing the battery nega-
tive (±) terminal, but in this case, other memory
systems (clock, etc.) will also be cancelled out.
wIf the diagnostic code is not cancelled out, it will be retained
by the ECU and appear along with a new code in the event
of future trouble.
wIf it is necessary to work engine components requiring re-
moval of the battery terminal, a check must first be
made to see if a diagnostic code has been recorded.
2. After cancellation, road test the vehicle to check that a normal
code is now read on the ºCHECKº engine warning
light.
If the same diagnostic code appears, it indicates that the
trouble area has not been repaired thoroughly.
DIAGNOSIS INDICATION
1. (2VZ±FE)
Including ºnormalº, the ECU is programmed with the follow-
ing 16 (Ex. CALIF.) or 18 (CALIF.) diagnostic codes.
2. When 2 or more codes are indicated, the lowest number
(code) will appear first.
However, no other code will appear along with code No.11.
3. All detected diagnostic codes, except code No.51, will be
retained in memory by the ECU from the time of detection
until cancelled out.
4. Once the malfunction is cleared, the ºCHECKº engine warn-
ing light on the instrument panel will go oft but the diagnos-
tic code(s) remain stored in ECU memory (except for code
No.51).
± EFI SYSTEMDiagnosis SystemFI±24

Check wiring between ECU terminal T (T1) and check
connector terminal TE 1, and ECU
terminal E 1 and check connector terminal El. Is there diagnostic code output when check
connector terminals TE 1 and E 1 and short
circuited? Does ºCHECKº engine warning light come on when
ECU terminal W is grounded to the body?
Does ºCHECKº engine warning tight come
on when ignition switch is at ON?
Check bulb, fuse and wiring between ECU and
ignition switch.
Does ºCHECKº engine warning light go out after
repair according to malfunction code? Does ºCHECKº engine warning light go off when
the engine is started?
Check wiring between ECU and ºCHECKº
engine warning light.Check wiring between
ECU terminal El and body
ground.
Cancel out diagnostic code. Further repair required.Try another
ECU.Try another
ECU.
Repair or replace.Repair or replace.
System Normal
System Normal
System OKRepair.
BAD
BAD
BAD
YES YES
YESYES
YES
± EFI SYSTEMDiagnosis SystemFI±30

EFI SYSTEM CHECK PROCEDURE
(3S±FE)
HINT:
wPerform all voltage measurements with the connectors con-
nected.
wVerify that the battery voltage is 11 V or more when the igni-
tion switch is in ºONº position.
Using a voltmeter with high impedance (10 kW/V minimum),
measure the voltage at each terminal of the wiring
connectors.
THROTTLE POSITION
SENSORTHROTTLE POSITION
SENSOR
THROTTLE POSITION
SENSOR
Terminals of ECU
NEUTRAL START
SWITCH
HEADLIGHT and
DEFOGGER EGR GAS TEMP.
SENSOR
WATER TEMP. SENSOR SUB±OXYGEN SENSORA/C MAGNET SWITCH
STOP LIGHT SWITCH
CHECK CONNECTORCHECK CONNECTORAIR FLOW METER
AIR FLOW METER
AIR FLOW METER STARTER SWITCH
SENSOR GROUND SENSOR GROUND ENGINE GROUND
ENGINE GROUND ENGINE GROUND
OXYGEN SENSOR
WARNING LIGHTA/C AMPLIFIER
SPEED SENSORTerminal name Terminal name Terminal name
DISTRIBUTORDISTRIBUTOR
DISTRIBUTOR
MAIN RELAYMAIN RELAY ISC VALVE
ISC VALVE INJECTORINJECTOR Symbol
BATTERY Symbol
Symbol
IGNITERECT ECUECT ECU
ECT ECU
IGNITER
ECT ECU
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±32

No trouble (ºCHECKº engine warning light off) and
engine running
Voltage at ECU Wiring Connectors (3S±FE)
Measuring plate fully closed
Intake air temp. 20°C (68°F)
Coolant temp. 80°C (1765F) Measuring plate fully open Throttle valve fully closed Throttle valve fully closed
Throttle valve open
Air conditioning ONThrottle valve open Throttle valve open
Cranking or idlingSTD voltage (V)
Terminals
3,000 rpmSee page Condition
IG SW ONIG SW ON
IG SW ON
IG
SW ONIG SW ON
IG SW ONCrankingIdling
FI±40
FI±44
FI±46FI±45FI±34
FI±43 FI±42
FI±47FI±35
FI±36
FI±37
FI±39
FI±41 No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±33

Check that there is voltage between ECU terminal W and
body ground.
Check wiring between ECU terminal El and body
ground. No voltage between ECU terminals W and E1.
(idling) No trouble (ºCHECKº engine warning light
off) and engine running
Check GAUGE fuse 7.5 A and ºCHECKº
engine warning light.
Check wiring between ECU
terminal W and fuse.Fuse blows again
BADRepair or replace.
Repair or replace. Repair or replace. Try another ECU.STD voltage
No voltageCondition
TerminalsTrouble
BAD
BAD No.
± EFI SYSTEMTroubleshooting with Volt/ OhmmeterFI±46

EFI SYSTEM CHECK PROCEDURE
(2VZ±FE)
PREPARATION
(a) Disconnect the connectors from the ECU.
(b) Remove the locks as shown in the illustration so that the
tester probe(s) can easily come in.
NOTICE: Pay attention to sections ºAº and ºBº in the il-
lustration which can be easily broken.
(e) Reconnect the connectors to the ECU.
HINT:
wPerform all voltage measurements with the connectors con-
nected.
wVerify that the battery voltage is 11 V or more when the igni-
tion switch is in ºONº position.
Using a voltmeter with high impedance (10 k

/V mini±
mum), measure the voltage at each terminal of the wiring
connectors.
AIR FLOW METER
THROTTLE POSITION SENSOR
Terminals of ECU
No. 1 SPEED SENSOR (Meter side)
No. 2 SPEED SENSOR (AlT side)
THROTTLE POSITION SENSOR FUEL PRESSURE CONTROL VSV
THROTTLE POSITION SENSORCRUISE CONTROL COMPUTER
* 1 w/ ECT
*2 CALIF. only KNOCK CONTROL SENSOR PATTERN SELECT SWITCH
OXYGEN SENSOR HEATER
NEUTRAL START SWITCHEGR GAS TEMP. SENSOR INJECTOR (No. 2 and 3)INJECTOR (No. 4 and 5)
SIFT POSITION SWITCH.
ISC MOTOR NO. 3 COILINJECTOR (No. 1 and 6i
ISC MOTOR NO. 1 COIL
ISC MOTOR NO. 4 COILSIFT POSITION SWITCH ISC MOTOR NO. 2 COILWATER TEMP. SENSORSUB±OXYGEN SENSOR
SIFT POSITION SWITCH COLD START INJECTOR
EFI MAIN RELAY (COIL)
SIFT POSITION SWITCHSUB±OXYGEN SENSOR CHECK CONNECTOR
COMPUTER GROUND
CHECK CONNECTORCHECK CONNECTOR CHECK CONNECTOR
AIR TEMP. SENSORA/C COMPRESSOR
SENSOR GROUNDTerminal Name
OXYGEN SENSOROD MAIN SWITCH
STARTER SWITCHIGNITION SWITCH Terminal Name
AIR FLOW METERTerminal Name
POWER GROUND
POWER GROUND
WARNING LIGHT
EFI MAIN RELAY BRAKE SWITCH
EFt MAIN RELAY ECT SOLENOID
ECT SOLENOIDA/C AMPLIFIER
ECT SOLENOIDDISTRIBUTOR
DISTRIBUTOR DISTRIBUTOR
DISTRIBUTOR
TEMS ECU
TEMS ECU
TEMS ECU Symbol Symbol Symbol
BATTERY IGNITER
IGNITER
*2NSW
*1OD2
No. 30 No. 10
No. 20
*1PWR
*2OX2
M±REL
*1OD 1
*2CHK
*2THGIG SW
*1SP2
BATT
*1SL
*1 DG
1S1THW
*1S2
*1BK
ISC4 1SC2 ISC1
ISC3VTAOX1
ACTS TJSP1
THA
STAKNK EO2 E01
IGT
*1R A/C
EPU
1
L
IGF
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±50

No trouble (ºCHECKº engine warning light off) and
engine running
Voltage at ECU Wiring Connectors
Coolant temp. 80°C (176°F) Measuring plate fully closed
Intake air temp. 20°C (68°F) Measuring plate fully open Throttle valve fully closed
Air conditioning ONThrottle valve open Throttle valve open
Cranking or idlingSTD voltage (V)
IG SW ON
1G SW ON
IG SW ONCondition
IG SW ONIG SW ON
IG SW ON TerminalsSee page
CrankingIdling
FI±63FI±62FI±58
FI±60 FI±59FI±57
FI±65FI±64FI±52
FI±61FI±55
rpm No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±51

Check that there is voltage between ECU terminal W and body
ground. There is no voltage between ECU terminals W and E1.
(Idling)
Check wiring between ECU terminal E 1 and body
ground. '
Check GAUGE fuse 7.5A and ºCHECKº
engine warning light. No trouble (ºCHECKº engine warning light off)
and engine running
Check wiring between ECU terminal
W and fuse.Fuse blows again
Repair or replace.Repair or replace.
Repair or replace.
Try another ECU.STD voltage
No voltage Terminals ConditionTrouble
NO
BAD
BAD No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±64