ECU TOYOTA CAMRY V20 1986 Service Information

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 BATT and body
ground.
Check wiring between ECU terminal E1 and body ground.
Check wiring between ECU terminal and
battery.There is no voltage between ECU terminals BATT and El.
Check fuse and fusible link.Repair or replace.
Repair or replace. Try another ECU.
wBATT ± E1
STD voltage
No voltage
Terminals
IG SW ON
Condition
Replace. Trouble
BADBAD
BADNo.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±52

Check that there is voltage between ECU terminal M±REL and body
ground. (IG SW ON)Check that there is voltage between ECU terminal IG SW and body
ground. (IG SW ON).
There is no voltage between ECU terminals M±REL and El.
(IG SW ON)There is no voltage between ECU terminals IG SW and El.
(IG SW ON)
Check wiring between ECU terminal E 1 and body
ground.Check wiring between ECU terminal E t and body ground.
Check EFI main relay and wiring
harness. (See page F!±121 )Check fuse, fusible link and
ignition switch.
Repair or replace.Repair or replace. Repair or replace.
Try another ECU.
Try another ECU.
Try another ECU.
wM±REL ± E1 wIG SW ± E1
Replace. BADBAD
BAD
BAD
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±53

Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON) There is no voltage between ECU terminals +B (+B1) and
E1. (IG SW ON)
Check wiring between ECU terminal E1 and body
ground. .
Check fuse, fusible link and wiring
harness.
Refer to M±REL ± E1 trouble
section.Check EFI main relay.
(See page FI±121 )
w+B(+B1)±E1
Repair or replace. Try another ECU.Repair or replace.
Replace.BAD
BAD
BAD
± EFI SYSTEMTroubleshooting with Volt ohmmeterFI±54

Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)There is no voltage between ECU terminals IDL and E2. (IG SW
ON) (Throttle valve open)
Check wiring between ECU terminal E 1 and body
ground.
Check wiring between ECU and
throttle position sensor. Check throttle position sensor.
(See page FI±112)
Repair or replace throttle
position sensor.Throttle valve fully closed
Refer to No. 1.
(See page FI±51) Throttle valve fully openThrottle valve open
Repair or replace.
Repair or replace.
Try another ECU. Try another ECU.
wIDL ± E2
STD voltage
No voltage
IG SW ON Terminals
Condition Trouble
BAD
BADBAD
BAD
No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±55

Check that there is voltage between ECU terminal VC and E2.
(IG SW ON) Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
There is no specified voltage at ECU terminals VTA and E2.
(1O SW ON) There is no voltage between ECU terminals VC and E2.
(IG SW ON)
Check wiring between ECU and throttle
position sensor.
Check wiring between ECU and
throttle position sensor.Check throttle position sensor.
(See page FI±112)
Check throttle position sensor.
(See page FI±112) Refer to VC ± E2 trouble
section.Repair or replace
wiring. Refer to No. 1.
(See page FI±51 )
Repair or replace.
Repair or replace.
Repair or replace.
Try another ECU. Try another ECU.
wVTA ± E2 wVC ± E2
BAD
BAD BAD
BAD
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±56

Check that there is voltage between ECU terminal +B (+Bl)
and body ground. (IG SW ON) There is no voltage between ECU terminals VC or VS and E2.
(IG SW ON)
Check wiring between ECU terminal E 1 and body ground.
Check wiring between ECU and air flow
meter. Check air flow meter.
(See page FI±104)
Measuring plate fully closed
Refer to No. 1.
(See page FI±52) Measuring plate fully open
Replace air flow
meter.Repair or replace.
Repair or replace.
Try another ECU.STD voltage
No voltage
3,000 rpmIG SW ON TerminalsCondition
Trouble
Idling
¿ OK
BAD
BAD BAD No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±57

There is no voltage between ECU terminal No. 10, No. 20
and/or No. 30 and E41 and/or E02. (IG SW ON)
Check that there is voltage between ECU terminal No. 10,
No. 20 or No. 30 and body ground.
Check wiring between ECU terminal E01 and/or
E02 and body ground.
Check resistance of magnetic coil in each injector.
STD resistance: Approx. 13.8

Check wiring between ECU
terminal No. 10, No. 20 and/or
No. 30 and battery.Check fusible link and
ignition switch.Repair or replace.
Try another ECU.
Repair or replace. Repair or replace.
Replace injector.STD voltage
No voltage
IG SW ON
Terminals
Condition Trouble
No.
BADBAD
BAD
BAD
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±58

Check that there is voltage between ECU terminal +B (+B1 )
and body ground. (IG SW ON)There is no voltage between ECU terminals THA and E2.
(IG SW ON)
Check wiring between ECU terminal E1 and body ground.
Check wiring between ECU and air temp.
sensor. Intake air temperature 20°C (68°F)
Check air temp. sensor.
(See page FI±104)Refer to No. 1.
(See page FI±52)
Replace air flow
meter.Repair or replace.
Repair or replace.
Try another ECU.STD voltage
No voltage
IG SW ON
TerminalsCondition Trouble
BADBAD
BAD No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±59

Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON) There is no voltage between ECU terminals THW and E2.
(IG SW ON)
Check wiring between ECU and water temp.
sensor. Check wiring between ECU terminal E1 and body ground.
Check water temp. sensor.
(See page FI±125) Coolant temperature 80°C
(176°F)
Refer to No. 1.
(See page FI±52)
Replace water
temp. sensor.
Repair or replace.Repair or replace.
Try another ECU.STD voltage
No voltageIG SW ON Terminals
Condition
Trouble
BADBAD
BAD No.
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±60