1987 TOYOTA CELICA Service Repair Manual

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA)
JO. Terminals Trouble Condition
S-m Voltage
No. IO
EOl
5 No. 20 -
E02 No voltage Ignition switch ON 9-14v
No. 30
Fusible
Link
8 MAIN 2.OL
-T
T
Battery f
-
I
= -“No. 10
I c
FIZE
Ignition Switch ECU
No. 2C
Voltmeter
A Solenoid Resistor
nr R?r
0 There is no voltage between ECU terminal No. 10, No. 20
and/or No. 30 and EOl or E02. (IO S/W ON)
1.
0 Check that there is specified voltage between resistor terminal
+B and body ground. STD voltaae: 9 - 14 V
1 NO 1
.
Check fuse, fusible links BAD
and ignition switch. - Repair or replace.
I i
1 OK I
I I ,
1
Check wiring between
resistor and battery. BAD
- Repair or replace.
Check that there is specified voltage between resistor terminal
@ (No. IO, No. 20 or No. 30) and body ground.
j ‘,.“.““!
I 0
Check resistance of magnetic coil in
each lniector. I 1 Replace resistor.
I
I . J I I

FI-48 EFI SYSTEM - Troubleshooting with Volt/Ohmmeter.(MA)
I
7M-GE
@
.-
Air Flow Meter
UO.
6 Terminals
THA - E2 Trouble Condition ._ ST0 Voltage
No voltage IG S/W ON Intake air temperature 20°C (68°F) 1 -3v
IM-GE
1 I Air Temp. Sensor
(Air Flow Meter) ECU
+B
(+Bl)
E2
THA
lE1 7M-GTE
ir Temp. Sensor
iir Flow Meter)
1
I THA
E2
I
ECU
CB
-i-B11
l-HA
0 There is no voltage between ECU terminals THA and E2.
(IG S/W ON)
1
Fl1636
‘M-GTE
Ohmmeter Air Flow Meter
I/ 1” THA / Check that there is voltage between ECU terminal +B (+Bl) and
body ground. (IO S/W ON)
I
OK NO
Refer to No. 1.
(See page FI-4 I)
Check wiring between ECU terminal El and body ground.
OK
t
I I I
0 Check air temp. sensor.
(See pages FI-96, 98)
L * 1 Repair or replace. ]
I
I
BAD OK
Replace air flow Check wiring between ECU and air
meter. temp. sensor.
L k
OK
Try another ECU. Repair or replace.

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA) Fl-49
-.
No.
Terminals Trouble
Condition
STD Voltage
7 THW - E2 No voltage ignition switch
Coolant temperature 80°C
ON (1780~) o-q - l-0 V
ECU
Water Temp. Sensor
. iB (+Bll
THW
E2
El
Jf /
Voltmeter
n F1031:
1
0 There is no voltage between ECU terminals THW and E2.
(IO S/W ON)
1 i
CD Check that there is voltage between ECU terminal +B (+Bl) and
body ground. (IG S/W ON)
1
OK
NO
Refer to No. 1.
(See page FI-41)
Check wiring between ECU terminal El and body ground.
OK
, 1
0 Check water temp. sensor.
(See page FI-1 161
I I
Try another ECU. OK
Check wiring between ECU and water
temp. sensor.
OK BAD
Repair or replace.

1-50
No.
6 EFI SYSTEM - Troub&hooting with Volt/Ohmmeter (MA)
Terminals Trouble Condition STD Voltage
STA - El No voltage Cranking 6-14V
Fusible Link
ALT
7M-GE.
I.258
7M-GTE
1 OOA
MAIN 2.01
Battery (M/T)
Fusible Ignition
Link Switch
Idal :
Neutral Start S/W
(A/T)
To Circuit Starter
a
,ening Relay (STAI ECU
3TA ,
El
loltmeter
lF!L V’
FlO3:
‘ottmeter 0
Starter
0 There is no voltage between ECU terminals STA and .El .
II0 S/W START)
Check starter OK Check wiring between ECU terminal STA
operation. and ignition switch terminal STI.
L
BAD OK
I BAD
I 1
I
1 Repair or replace.
I I 1
I
I
0 Check wiring between ECU terminal El and body
around.
I
Check fusible links, battery, wiring,
ignition switch and neutral start
switch. BAD
e Repair or replace.
OK
’
I
0
Check that there is voltage at STA (50) terminal of starter.
(IO S/W START) STD voltage: 6 - 14 V
OK NO
I
1 Check starter. 1 Check wiring between ignition switch
terminal ST 1 and starter terminal STA (50).
L

EFI SYSTEM -. Troubleshooting with Volt/Ohmmeter (MA) FI-51
I-
i’
No. Terminals
Trouble Condition
STD Voltage
9 IGT, IGF - El
No voltage Idling
0.7 - 1.0 v
ECU
Fusible
Link
Battery Fusible Link Ignition Switch
AM2 30A
Tachometer
MAIN 2.OL
IGF
IGT
El
Voltmeter
EL It’-
Ohmmeter
0 There is no voltage between ECU terminals IGT and El.
(Idling)
I
I
0 Check that there is voltage between ECU terminal IGT and
body ground. (Idling)
I NO I OK
1
0 Check wiring between ECU BAD Repair or
terminal El and body ground. replace.
I
Check fusible links and ignition
switch. Repair or replace.
I
1 I I I
1 OK
Check distributor or cam position
BAD
sensor. (See pages IG- 11, 18) - Repair or replace.
I
1 OK
Check wiring between ECU and
battery. BAD
*-Repair or replace.
I
I I L I
1 OK
Repair or replace.

FI-52 EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA)
No.
‘10 Terminals
lGdA - El
IGdS Trouble
No voltage
._
Condition
idling STD Voltage /
1 -3V
‘7M-GTE only
Fusible
Link
AM2
30A Ignition
Switch
AM241G2
T
Battery 1
L
I
= TO
7 Tachometer
niter
L
I
=
ECU
IGdA
IGdB
El
Joltmeter
F1195
-l
0
There is no voltage between ECU terminals IGdA or IGdB and
El. (Idlinal
0 Check that there is voltage between ECU terminal IGdA or
IGdB and body ground. (Idling)
,
I
I , NO 1 9
0
Check wiring between ECU BAD Repair or
L
terminal El and body ground. replace.
OK
Try another ECU.
Check fusible links and ignition BAD
switch. - Repair or replace.
c
I
I 1
I r 1 Check cam position sensor.
(See page IG-18)
I Repair or replace.
I
Check wiring between ECU and
batter-v. Repair or replace.
I 1 J
I
BAD
I I I

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA) FI-53
No.
Terminals
Trouble Condition
STD Voltage
11 ISCl - ISC4 - El No voltage
Ignition switch ON
g-14v
Fusible
Link EFI Main Relay
ISC Valve
Fuse
EFI 15A
Fusible
Link
h MAIN 2.OL AM2 30A
I
, ECU
ISCI
ISC2
ISC3
ISC4
+B
+Bl
M-REL
01
doltmeter
@I
Bl
V
PI
Y
I Fk-n12
Fl16431
0 There is no voltage between ECU terminals ISCl - ISC4 and
El. (IG S/W ON1
0 check that there is voltage between ECU terminal +B (+Bl)
and body ground. UG S/W ON)
OK
1 Check wiring between ECU terminal El and body ground. 1
I OK
0 Check ISC valve.
(See page.FI-I 08)
, 1 Repair or replace. )
I
Replace ISC
I I Check wiring between ECU and EFI
valve.
main relay.
I

EFI SYSTEM - Troub!eshoo$ng with Volt/Ohmmeter (MA)
. .
JO. Terminals
12 W - El Trouble
No voltage Condition
Nq @uble, (“CHECK” engine warning
light off) and engine running STD Voltage
s-14v
FUSE
GAUGE 7.5A
i
f “CHECK ENGINE”
Wahiing Light
Combination Mete W
El
FlO7
Joltmeter
EL v “_
Fl1251
1
Voltmeter
FH25C
. .
~0 There is no voltage between ECU terminals W and El.
(Idlin$
,
.
I 0
Check that there is voltage between ECU terminal W and
I
hod
Q;
0 Check wiring between ECU terminal El and body
Check GAUGE fuse (7.5A) and “CHECK
ENGINE” warning light.
I I
I Repair or replace.
I
1
Check wiring between ECU terminal BAD
*
W and fuse. Repair or replace.
I I
1 I