1987 TOYOTA CELICA engine

EFI SYSTEM - Diagnosis System FI-29
MS EFI 15iA
LHD
EFI 15A
EFI 15A
R16C
FI26:
CANCELLING OUT DIAGNOSTIC CODE
1.
2. After repair of the trouble area, the diagnostic code
retained in memory by the ECU must be cancelled out by
removing the EFI fuse 15A for 30 seconds or more,
depending on ambient temperature (the lower the tem-
perature, the longer the fuse must be left out) with the
ignition switch off.
NOTE:
l Cancellation can also be done by removing the battery”
negative (-1 terminal, but in this case other memory
systems (clock etc.) will also be cancelled out.
l If the diagnostic code is not cancelled out, it will be
retained by the ECU and appear along with a new code
in event of future trouble.
l If it is necessary to work on engine components requir-
ing removal of the battery terminal, a check must first
be made to see if a diagnostic code has been recorded.
After cancellation, road test the vehicle to check that a
“normal” code is now read on the “CHECK ENGINE”
warning light.
If the same diagnostic code is still indicated, it means that
the trouble area has not been repaired thoroughly.
DIAGNOSIS INDICATION
(I) 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.
(2) All detected diagnostic codes, except 51 and 53, will be
retained in memory by the ECU from the time of detection
until cancelled out.
(3) Once the malfunction is cleared, the “CHECK ENGINE”
warning light on the instrument panel will go out but the
diagnostic code(s) remain stored in ECU memory (except
for codes 51 and 53).

I-30 .EFl SYSTE.M - Diagnosis System
DIAGNOSTIC CODES (MA)
Trouble area
I See
page Code Number of
; No. Che;;;;gine System
I
- nnrulno4 Norma’ Diagnosis
This appears when none of
the other codes area identified.
0
Ignition switch circuit
Ignition switch T
Main relay circuit
1 Main relay
1 ECU FI-41
1 Distributor circuit
r Distributor
) Starter signal circuit
b ECU
) Distributor circuit
B Distributor
B ECU IG-3
IG-3 ECU (+B) fl n Momentary interruption in 0
11
power supply to ECU.
I 0
l
Jo “NE” or “G” signal to
ICU within 2 seconds after
engine has been cranked.
Uo “NE” signal to ECU when
sngine Sp88d is above
1,000 rpm.
No “IGF” signal to ECU
i- 8 times in succession.
Ietectinn of oxygen sensor
jeterioration. E
t
C
i
P. Open or short circuit in wate
temp. sensor signal.
Open or short circuit in intake
air temp. sensor signal.
I7M-GE)
Air-flow
Meter Signal Open circuit in VC signal or
short circuit between VS and
E2 when idle contacts are
c tosed.
(7M-GTE)
Open or Short circuit in air
flow meter signal.
(‘IM-GE)
Open circuit in E2 or short
circuit between VC and VS.
(‘IM-GTE)
Open or short circuit in HAC
sensor signal
Turbocharger
Pressure ‘3
Turbocharger pressure is
abnormal. B Ignition and ignition coil
circuit
8 Igniter and ignition coil
0 ECU !I-5 1
gnition Signal
l-l 2
FI-4’
Fl-48
I!
(
!
1
,-
1
Fll608
nn n
FIl609
FI-44
d )r FI-4‘
FI-51
Open or short circuit in circuit
I Sensor Signal throttle position sensor signal. 0 Throttle position sensor
0 ECU
SHl,d , FI-4 0 Oxygen sensor circuit
l Oxygen sensor
0 ECU
0 Water temp. sensor
@muit
‘8 Water temp. sensor
l ECU
0 Intake air temp. sensor
circuit
8 Intake air temp. sensor
. ECU 3xygen Sensor
signal
Water Temp.
Sensor Signal Fll81t
Intake Air Tern
Sensor Signal 24
Fll81
0 Air flow meter circuit
0 Air flow meter
0 ECU
Fl161 0 Air flow meter Circuit
0 Air flow meter
0 ECU
0 HAC sensor circuit
l HAC sensor
l ECU
0 Turbocharger
8 Air flow meter
0 Intercooler system
0 ECU (‘IM-GE)
Air Flow
Meter Signal
(7M-GTE)
HAC Sensor
Signal Fl18
i-
,
0 Throttle position s8nsC I FIZE
n

EFI SYSTEM
- Diagnosis System
FI-31
DIAGNOSTIC CODES (MA) (Cont’d) __
:odc
No. Number of
Check engine
blinks Diagnosis System See
page
FL50 Trouble area
l Vehicle speed sensor
circuit
l Vehicle speed sensor
. ECU ’
I
l Ignition switch circuit
l Ignition switch
l ECU
l Knock sensor circuit
l Knock sensor
l ECU
. ECU
l A/C switch circuit
l A/C switch ‘“q
l A/C am&fire
l Neutral start switch
circuit ’
l Neutral start switch
0 Throttle position sensor
circuit
l Throttle position sensor
l ECU Vehicle Speed
Sensor Signal
Starter Signal No “SPD” signal for 5
seconds when engine speed
is between 2,500 rpm and
4,500 rpm and coolant temp.
is below 80°C (176’F) except
when racing the engine.
No “STA” signal to ECU until
engine speed reaches 800
rpm with vehicle not moving.
Knock Sensor
Signal Open or short circuit in knock
sensor signal. 42
FI161
FHBl
Fl181
FIlei
52
Knock control in ECU faulty. Knock Control
signal in ECU
No “IDL” signal, “NSW”
signal or “A/C” signal to
ECU, with check terminals
El and T shorted. Switch Signal
‘1 WI TWC vehicles only
‘2 7M-GTE only
“3 Abnormalities in the air flow meter may also be detected.
DIAGNOSTIC CODES (MS)
Number of
Check engine
System
blinks
m Normal
fl1604
nn ECU (B) Diagnosis
This appears when none of
the other codes are identified.
Momentary interruption in
power supply to ECU. Trouble area See
page
l Ignition switch circuit
l Ignition switch
l Main relay circuit
l Main relay
l ECU FI-62
l Distributor circuit
0 Distributor
l Starter signal circuit
. ECU IG-3
l Distributor circuit
l Distributor
. ECU IG-3
l Igniter and ignition coil 11
FI1605
n nn RPM Signal No “NE” or “G” signal to
ECU within 2 seconds after
engine has been cranked.
FHBOB
nnnn, RPM Signal No “NE” signal to ECU when
engine speed is above
Fl1807 1,000 rpm. 12
-
13
-
14
-LJUlJUL 1 Ignition Signal 1 * No. “IGF” signal to ECU
6 - 8 times in succession. circuit
0 Igniter and ignition coil
. ECU
.t Fl-70

FI-32 EFI SYSTEM - Diagnosis System
1 ode -
: Number of See
Check engine System Diagnosis Trouble area
paw
blinks
0 Water temp. sensor
. .
clrcult m n FI-68
0 Water temp. sensor
0 ECU _
FllBlO 0 Intake air temp. sensor
r
JUMJJJL Intake Air Temp. Open or short circuit in intake circuit
FI-67
Sensor Signal air temp. sensor signal. 0 intake air temp. sensor
. ECU
fll611
Open circuit in VC signal or
0 Air flow meter circuit
JJJJ n f
‘. ‘( <;
closed.
F11612 .
i Air flow meter circuit
DIAGNOSTIC CODES (MS) (Cont’d)
4-65
32
Fl1613 I I
I 0 Throttle position sensor
Open or short circuit in circuit
41 throttle position sensor signal.
! 0 Throttle position sensor
. ECU
Fl1614
No “SPD” signal for 5
seconds when engine speed
0 Vehicle speed sensor
42 nnnruvl
is below 80°C (176°F) except
when racing the engine.
fl16151
I
No “STA” sianal to ECU until 0 Ignition switch circuit
43
i m Starter Signal /~~n~i,‘,pee~;~ct-;~~~ng : ;;;on switch FI-6!
FM
FM
? -. Fl1616 .^
0 Knock sensor circuit
52
.I JjJJMJjn Eyn$ Sensor ~~n~op:~~ circuit in knock : :gk sensor
53
I F11616
w6,9 Kn$c~i~“,“,‘;“’ Knock control in ECU faulty. l ECU
0 A/C compressor relay
A/C Com-
Open or short circuit in circuit
pressor
Relay Signal A/C compressor relay signal. a A/C compressor relay
. ECU
f12611
0 A/C switch circuit Z
51
No “IDL” signal, “NSW” 0 A/C switch
0 A/C amplifire l Neutral start switch
circuit
0 Neutral start switch
0 Throttle position sensor
circuit
I F11617
0 Throttle position Sensor
. ECU

EFI SYSTEM
- Diagnosis System
FI-33
INSPECTION OF DIAGNOSIS .ClRCUlT
._
Fuse IGN
“CHECK ENGINE”
Fl291
1.
I Dose “CHECK ENGINE” warning light come
on when ignition switch is at ON?
l-l YES System Normal
Does “CHECK ENGINE” warning light come Check wiring between
on when ECU terminal W is grounded to the
YES ECU terminal El and body OK Try another
body? - ground. __c ECU
+NO
Check bulb, fuse and wiring between ECU and
ignition switch. + SAD
Repair or replace
Does “CHECK ENGINE” warning light go off
when the engine is started? YES
. System Normal
NO
Check wiring between ECU and
“CHECK ENGINE” warning light.
1 OK
Is there diagnostic code output when check
connector terminals T(MA) or TEl (MS) and
El are short circuited? t
Check wiring between ECU terminal T and check
NO connector terminal T(MA) or TEl (MS), and ECU
* terminal El and check connector terminal El.
I I
I I
YES
Does “CHECK ENGINE” warning light go out NO
after repair according to malfunction code? ) Further repair required.
&
System OK Cancel out diagnostic code.

-34 EFI SYSTEM - Troubleshooting with Volt/dhmmeter (MA)
. .
TROUBLESHOOTING WITH
VOLT/OHMMETER (MA)
OTE: The following troubleshooting pro-
sdures are designed for inspection of each separ-
te system, and therefore the actual procedure
lay vary somewhat. However, troubleshooting
hould be performed refering to the inspection
lethods described in this manual. 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.
Jefore beginning inspection, it is best to first make
3 simple check of the fuses, fusible links and the
:ondition of the connectors. If engine trouble occurs even though proper
operating voltage is detected in the computer con-
nectar, then it can be assumed that the ECU is
faulty and should be replaced.
LOCATION OF FUSES AND FUSIBLE LINKS
No.
r 1 Relay Block (RHD)
I
61 I
No. 1 Relay Block (LHD)
Fuse IGN’ Fusible Link
ALT
(7M-GE) 1.259
(7M-GTE) 1 OCjA Fuse IdN 7.5A
EFI Main Relay
No. 2
Relay Block
Fusible Link
AM2 30A Fuse EFI 15A

EFI SYSTEM - Troubleshooting with’ Volt/Ohmmeter (MA) FI-37
Voltage at EClJ Wiring .Connectors (TIM-GE)
IO. Terminals
Condition STD Voltage
See page
BATT - El
10 - 14 FI-39
IG S/W - El
1 FI-40
M-REL - El
Ignition S/W ON 10 - 14
+B (+Bl) - El FI-41
IDL - E2 Throttle valve open 10 - 14 FI-42
vc - E2 -
4-6
2 Ignition S/W ON -
Throttle valve fully ‘closed 0.1
- 1.0 FI-43
VTA - E2
Throttle valve fully open 4-5
VC - E2 4-6
Ignition S/W ON
Measuring plate fully closed 4-5
3 Measuring plate fully open 0.02 - 0.08 FI-44
VS - E2
Idling 2-4
3,000 rpm 0.3 - 1.0
No. 10 EOI
5 No. 20 - Ignition S/W ON 9 - 14 FI-47
No. 30 E02
6 THA - E2 Ignition S/W ON Intake air temperature 20°C (68°F) 1 -3 FI-48
7 THW - E2 Ignition S/W ON Coolant temperature 80°C II 76’F) 0.1 - 1 .O
FI-49
8 STA - El Cranking
6 - 14 FI-50
9 IGF, IGT - El Idling
0.7 - 1.0 FI-5 1
11 ISCI
I&4 - El Ignition S/W ON 9-14 Fl-53
12 W - El No trouble (“CHECK ENGINE” warning light off) and
engine running 8 - 14 FI-54
13 A/C - El Air conditioning ON IO - 14 FI-55
ECU Terminals
‘~,~] E2 4
/UC W:G up +S :,:I
N:y Is’ Is’ GO Gl G2 NE IGT IGF THW OX “s, “;“riL EGR SPD FPR THA VS VC BATT IG
F1057

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter (MA)
. .
Voltage at ECU Wiring Connectors (7M-GTE)
No. Terminals
Condition STD Voltage Sea page
BATT - El 10 - 14
FI-39
IG S/W - El
1
FI-40
M-REL - El Ignition S/W ON 10 - 14
+B (+Bl) - El
FI-41
*
IDL - E2 Throttle valve open 10 - 14 FI-42
VC - E2 4-6.
2 . Ignition S/W ON
Throttle valve fully closed 0.1 - 1.0 FI-43
VTA - E2
Throttle valve fully open 4-5
i
KS - Body Ignition S/W ON 4-6
FI-45
gnMid
4 Cranking or running 2-4
vc - Body
Ignition S/W ON 4-6
groulld Fl-46.
No. 10 EOl
5 No. 20 - Ignition S;W CN 9 - 14 Fl-47
No. 30 E02
6 THA - E2 Ignition S/W ON Intake air temperature 20°C (68°F) 1 -3 FI-48
7 THW - E2 Ignition S/W ON Coolant temperature 80°C (176°F) 0.1 - 1 .O FI-49
8 STA - El Cranking 6-14 FI-50
9 IGF, IGT - El Idling 0.7 - 1.0 FI-5 1
10 IGdA, IGdB - El Idling 1-3 FI-52
11 I Cl
7 9 - 14 FI-53
ISC4 - El Ignition S/W ON
12 W - El No trouble (“CHECK ENGINE” warning light off) and
engine running 8 - 14 FI-54
13 A/C - El
14 HAC - E2 Air conditioning ON 10 - 14
FI-55
540 mmHg (21.26 in.Hg. 72.0 kPa) Approx. 2.8
Ignition S/W ON FI-56
750 mmHg (29.53 in.Hg, 100.0 kPa) Approx. 3.6
ECU Terminals
I U 1 I -
I
1
‘yc ‘;c GQ Gl G2 NE IGT IGF ~Hln, OX “;’ HT r;,
EGR SPD FPR THA HAC VC ‘JAn& 0 DF
‘;’ ‘sd: VF T VTA IDL
WA ““1” K;K E2 Ll L2 L3 NC W OIL ECT FC KS +B +Bl m
TIL LP