1987 TOYOTA CELICA Service Repair Manual

No. Terminals
13 A/C - El Trouble
No voltage , Condition
Air conditioning ON STD Voltage
10 - 14 v
A/C
Amplifier T
Lllintl NC Compressor ECU
NC
El
Voltmeter
F1125
Voltmeter
Ohmmeter
0 There is no voltage between ECU terminals A/C and El.
(Air conditioning ON)
I i
I 0
Check that there is voltage between ECU terminal A/C and 1
bodl y ground.
I
NO OK .‘.
0 Check wiring between ECU terminal El and body
ground.
BAD
terminal A/C and
Check that there is voltage between
BAD
amplifier terminal and body ground. c Repair or replace.
I c
1 OK
Check wiring between amplifier and BAD
ECU or compressor. * Repair or replace.

;6 EFI SYSTEM .L Troubleshooting with VoWOhmmeier (MA)
0. Terminals
r4 HAC - E2
7M-GTE only Trouble ‘Z’ ‘f .: ‘I *-
Condition STD Voltage
;> :
1 ‘Ig+i@ 540 mmHg (2l,.26 h.Hg, 72:O !Pa) Approx. 2.8 V
No voltage
S/W ON
750 mmHg (29.53 in.Hg, 100.0 kPa) Approx. 3.8 V
To Air Flow Meter-
Her Flow Meter ECU
1 HAC
bE2.
2,000 0 Alitude (m)
1,000
FI1995Fil99
.,~ .._ .,_
I... ~ _ . . ., , .
,.;_
itage between ECU terminal HAC and E2.
.,, ”
Check that there is voltage between ECU tdrminal VC and
body ground. (IG S/W ON)
,..
.._
Refer to No. 2.
(See page FI-43)
,. . . .
Voltmeter
EL . 1,
.v ‘_
E2 VC
b
FI199
Check wiring between ECU terminal El and body ground.
BAD
.
0 Check HAC sensor.
(See page FI-121) Repair or replace.
4
. ...<,
BAD OK
Replace HAC Check wiring between ECU and HAC
sensor. sensor.
OK BAD
Try another ECU.
I Repair or replace.

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MS) FI-57
-.
TROUBLESHOOTING WITH
VOLT/OHMMETER (MS)
NOTE: The following troubleshooting pro-
cedures are designed for inspection of each separ-
ate system, and therefore the actual procedure
may vary somewhat.. However, troubleshooting
should be performed refering to .the inspection
methods described in this manual. .._
Before beginning,inspection, it is best to first make
a simple check of the fuses, fusible links and the The following troubleshooting procedures are
based on the supposition that the trouble ‘lies in
either a short or open circuit in a component out-
side the computer or a short circuit within the
computer.
If engine trouble occurs even though proper.
operating voltage is detected in the computer con-
nector, then it can be assumed that the ECU is
faulty and should be replaced.
LOCATIoN- OF FUSES AND FUSIBLE LINKS
condition of the connectors.
Junction Block and Relay Block Cassettes

jS EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MS)
-.
0
“B”
Fl294.
ECU
EFI SYSTEM CHECK PROCEDURE
._
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.
CAUTION: Pay attention to sections “A” and “B” in
the illustration which can be easily broken,
(c) Reconnect the connectors to the ECU.
’
NOTE:
0 Perform ail voltage measurements with the connectors
connected.
0 Verify that the battery voltage is 1 IV or above when
the ignition switch is at “ON”.
Using a voltmeter with high-impedance (10 kQ/V mihimum),
measure the voltage at each terminal of the wiring con-
nectors.
Terminals of ECU
rmbol Terminal Name Symbol Terminal Name
Symbol Terminal Name
EOI POWER GROUND NE DISTRIBUTOR ACPS A/C PRESSURE SWITCH
co2 POWER GROUND El COMPUTER GROUND SPD SPEEDOMETER
o. 10 INJECTOR (No. 1 and 4) VF CHECK CONNECTOR ECT ECT COMPUTER
o. 30 INJECTOR (No. 3 and 5)
GO DISTRIBUTOR ACR A/C COMPRESSOR
o. 20 INJECTOR (No. 2 and 6) TE2 CHECK CONNECTOR Ll
ECT COMPUTER
ELS DEFOGGER SWITCH
HEADLIGHT SWITCH TEl CHECK CONNECTOR L2
ECT COMPUTER
FPU VSV (FPU) KNK KNOCK SENSOR FPR FUEL PUMP RELAY
ACV VSV (A/R CONTROL) THW WATER TEMP. SENSOR L3 ECT COMPUTER
SC 1 ISC MOTOR NO. 1 COIL IDL
THROTTLE POSITION SENSOR W
WARNING LIGHT
IGT IGNITER THA AIR TEMP. SENSQR
M-REL EFI MAIN RELAY (COIL)
SC- ISC MOTOR NO. 2 COIL VTA THROlTLE POSITION SENSOR IG SiW IGNITION SWITCH 3
ISC3 ISC MOTOR NO. 3 COIL vs AIR FLOW METER Bl EFI MAIN RELAY
ISC4 ISC MOTOR NO. 4 COIL vcc AIR FLOW METER
THROTTLE POSITION SENSOR BATT BATTERY
IGF IGNITER E2
SENSOR GROUND B
EFI MAIN RELAY
G2 1 DISTRIBUTOR 1 STA 1 STARTER SWITCH
Gl 1 DISTRIBUTOR 1 NSW 1 NEUTRALSTARTSWITCH
ZU Terminals

EFI SYSTEM - Ttpbleshooting with Volt/Ohmmeter (MS)
FL59
IO.
I Terminals
BATT - El
IG S/W - El
M-REL - El
2P-
I UTA - E2
3
US - E2
THA - E2
THW - E2
.B / IGF, IGT - El
9 ISCI
lSC4 - El
10
I W - El
ECU Terminals
Voltage at ECU Wiring Connectors
Condition STD Voltage ’
10 - 14
ignition S/W ON
10 - 14
Throttle valve open 10 - 14
4-6
Ignition S/W ON .
Throttle valve fully closed 0.1 - 1.0
Throttle valve fully open
4-5
4-6
Ignition S/W ON Measuring plate fully closed
4-5
Measuring plate fully open
0.02 - 0.08
Idling 2-4
3,000 rpm 0.3 - 1 .o
Ignition S/W ON 9
- 14 FI-66
Ignition S/W ON Intake air temperature 20°C (68°F) 1
-3
Ignition S/W ON
Coolant temperature 80°C (176°F) 0.1 - 1.0
Cranking
6 - 14
Idling 0.7 - 1.0
Ignition S/W ON
9 - 14
No trouble (“CHECK-ENGINE” warning light off) and
engine running 8 - 14 See page
FI-60
FI-6 1
FI-62
FI-63
FI-64
Fl-65
Fl-6.7
FI-68
FI-69
Fl-70
FI-7 1
Fl;72

FI-60 EFI SYSTEM - Troubleshooting with VoW6hmmeter (MS)
-.
No. Terminals Trouble Condition .
STD Voltage
BATT - El No voltage
lo- 14v
IO S/W - El
1 No voltage
Ignition switch ON lo-14v
M-REL - El No voltage Ignition switch ON
IO- 14v
B(B1) -El No voltage Ignition switch ON
10 - 14 v
-‘- Battery BATT ’
Bl
B
M-REL
IG S/W
El
@z
ECU
Fl275:
I Fl275,
ECU w
I Fl275
. BATT - El
@There is no voltage between ECU terminals BATT and El.
I
I
I 0
Check that there is voltage between ECU terminal BATT and
body ground.
I
NO OK
0 Check wiring between ECU terminal El and body
ground.
BAD
Replace.
1 OK
Check wiring between ECU terminal BAD
and battery. w Repair or replace.

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MS) FI-61
-.
ECU @
I ECU I
I ECU
. IG S/W - El
._
0 There is no voltage between ECU terminals IG S/W and El.
(IG S/W ON)
I
I
0
Check that there is voltage between ECU terminal IG S/W and
body ground. (10 S/W ON)
, 1
1
Check wiring between ECU terminal El and body
ground.
I
,
I I
Check fuse, fusible link and
ignition switch. BAD
) Repair or replace.
l M-REL - El
0
There is no voltage between ECU terminals M-REL and El.
(IG S/W ON)
1
‘
3 Check that there is voltage between ECU terminal M-REL and
body ground. (IG S/W ON)
NO OK
Che’ck wiring between ECU terminal El and body
ground.
OK BAD
Try another ECU.
1 Replace or repair.
F I
I I BAD
c Replace. Check EFI main relay and wiring
harness.

FI-62 EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MS)
ECU
Il--crl
I
I fl2911
I ECU @I
-- -
I’ I
II I R%
F12767 I
0 B (91) - El -’
I 0
There is no voltage between ECU terminals B (Bl) and El.
(IG S/W ON)
I
t
,
I
I 0
Check that there is voltage between ECU terminal B (Bl) and
body ground. (IG
S/W ON)
I
NO OK
Check wiring between ECU terminal El and body
ground.
Try another ECU.
I 1 Replace‘or repair. ]
Check fuse, fusible link and wiring BAD
harness. * Repair or replace.
I
1 OK
Check EFI main relay.
(See page FI-1 12) BAD
w Replace.
I OK
- El trouble
I