1987 TOYOTA CELICA Service Repair Manual

EFI SYSTEM - Electronic Control System
Fi-119
-.
High Temperature Line .Pressure Up System
To Circuit Opening Relay
4-r STA I
Air Temp. Sensor (Air Flow Meter)
VSVP
-f-HA
E2
THW
Water Temp. Sensor
Ohmmeter INSPECTION OF HIGH TEMPERATURE LINE
PRESSURE UP SYSTEM
I Fl1917
INSPECT VSV
A. Inspect VSV for Open Circuit
Using an ohmmeter, check that there is continuity be-
tween terminals.
Resistance: 30 - 60 n
If there is no continuity, replace the VSV.
1 B. Inspect VSV for Short Circuit
Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV.
-
I J FllSll
C. Inspect VSV Operation
(a) Apply battery voltage across the terminals.
(b) Check that air flows from pipe E to air filter.

-120 EFI SYSTEM - Electronic Control System
_.
I
I
F1192’
. . !c$ Diyrinect the battery.
(d) Check that air‘ flo.ws froril the pipe E and pipe G.
If operation is not as specified, replace the VSV.‘

EFI SYSTEM - Electronic Control System
FI-121
High Altitude Compensation (HAC)
System (7M.mGTE)
HAC Sensor ECU
Air Flow Meter 7
ov
I -._.. ,,nsor
From Throttle o HAC
on Sensor
t
Ai+ I o E2
) El
z
al
mnn I
T J.o -- ---- --_
Y r If
I /, / 1 INSPECTION OF HAC SENSOR
P
n199 zl
INSPECT RESISTANCE OF HAC SENSOR
(a) Remove the glove box.
(b) Using an ohmmeter, measure the resistance between
each terminal.
Terminals
vc - P
VC - E2
P - E2 Resistance
700 - 860 42
2.2 - 3.3 n
2.9 - 4.2 Q
, I
1
If the resistance is not as specified, replace the HAC sen-
sor.

22 EFI &STEM - Electronic Control S&m
El 7 Oxygen S,ensor (-WI TWC)
INSPECTrON OF OXYGEN SENSOR
1. WARM UP ENGINE
Allow the engine to reach normal operating temperature.
2. INSPECT FEEDBACK VOLTiGE (VFI
Connect the positive (+I probe of a voltmeter to terminals
n1711 VF of the check connector, and negative (-1 probe to ter-
minal El. Perfom the test as follows.
Narm up Oxygen sensor ‘with the engine at
!,500 rpm for approx. 90 seconds.
I
1
short termina!s T and El of the check connector.
4nd maintain engine speed at 2,560 ‘i-pm.
- / (,,,;,,.,,,,
i .
Check the number of times the voltmeter meedle fluctuates in 1 Oseconds. Zero again 1 After replacing
I the oxygen sensor
i ,. ., ;
: . .
Less than 8 times
t. ., .,
Warm up the oxygen sensor with the engine at
,,I
2,500 rpm for approx. 90 seconds. And maintain
engine at 2,500 rpm.
’
I
c
Check that the number of times the voltmeter
needle fluctuates in 10 seconds,
;- 8 times or more
Zero
Leis’~than 8 times
c
Unshort terminals T and El of the check connector.
And maintain engine speed at 2,500 rpm.
Measure voltaae between terminals VF and El.
I
More than 0 V t
Read and record diagnostic codes. (See page FI-30)
I I
Normal code
and code 21 Malfunction code(s)
(ex. code 21)
Repair the relevent diagnostic code.
ONTINUED ON PAGE FI-123 !ero

EFI SYSTEM - Electronic Control System FI-123
CONTINUED FROM PAGE FI-122
. .
t
8 (
epair the relevent diagnostic code.
Malfunction code(s)
(ex. code 21)
Read and record diagnostic codes. (See.page FL30)
Normal code
and code 21
t
Unshort terminals T and El of the check connector.
And maintain engine at 2,500 rpm.
I
I
M,easure voltage between terminals VF and El.
ov
t
1
Disconnect the PCV hose.
.
1 Measure voltage between terminals VF and El. 1
t
Replace the oxygen sensor Repair (Over lean) 5V
Disconnect the water temp. sensor connector and
connect resistor with resistance of 4 - 8 kS1 or
another coded water temp. sensor.
1
Short terminals T and El of the check connector.
I
I
Warm up the oxygen sensor with the engine at
I
1 2,500 rpm for approx. 90 seconds. And maintain 1
engine speed at 2,500 rpm.
Measure voltage between terminals VF and El.
I
I 5V

FI-124 EFI SYSTEM - Electronic Control System
-.
Ohmmeter 3. (‘IM-GTE)
INSPECT HEATERAESISiANCE OF OXYGEN
SENSOR
Using an ohmmeter, measure the resistance between the
terminals 2 and 3.
R8SiStaflC8:, 3.0 - 3.6 n
If the resistance is not as specified, replace the sensor.

I ECU
ul +B +B
r
MS
ECU
Electronic Controlled Unit (ECU)
._
INSPECTION OF ECU
NOTE:
The EFI circuit can be checked by measuring the
resistance and voltage at the wiring connectors of the
ECU. .
1.
(MS)
PREPARATION
(See page FI-58)
2. INSPECT VOLTAGE OF ECU
Check the voltage between each terminal of the wiring
connectors.
0 Turn the ignition switch ON.
0 Measure the voltage at each terminal.
NOTE:
0 Perform all voltage measurements with the connectors
connected.
0 Verify that the battery voltage is 11 V or more when the
ignition switch is ON.
Voltage at ECU Wiring Connectors
I I I Terminals STD Voltage t Condition
I
BATT - El
IG S/W - El
10 - 14
M-REL - El
Ignition S/W ON
.
IDL - E2
VC (VCC) -. E2
VIA - E2 4-6 Throttle valve open
4-6
Ignition S/W ON
0.1 - 1.0 Throttle valve fully closed
4-5 Throttle valve fully open
4-5
Measuring plate fully closed
Ignition S/W ON
0.02 - 0.08
“‘vs Measuring plate fully open
- E2
2-4 Idling
0.3 - 1 .o 3,000 rpm
4-6
*2KS Ignition S/W ON
- E2
2-4 Cranking or running
VC - E2-
THA - E2 4-6 Ignition S/W ON
1 -3 Ignition S/W ON Intake air temperature 20°C (68°F)
THW - E2 0.1 - 1.0 Ignition S/W ON Coolant temperature 80°C (I 76°F)

FI-126 EFI SYSTEM - Electronic Control &stem
Voltage at ECU W.jring Connectors (Cont’d)
.:. .I, ,,
Termlnals
Nov
10 EOI
No. 20 -
No. 30
E2
STD Voltage
6 L ,4-,: Condition
Ignition S/W ON
STA - El
ISCI
I -El
ISC4
,, : :
IGF, IGT - .E-1
*‘IGdA, lGd8 - El
:
‘2HAC - E2 6 - 14
9 - 14
-
I, .., ,i,
o .,.- i.;&& ,; ::
:,, ;;:3%
. . 1
Approx: 2.8
- Ignition S/w ON
Approlr. -3.6 L Cranking
,
Ignition S/W ON
Idling
Idling
540 mm Hg (21.26 in.Hg, 72.0 kPa)
750 mm Hg (I 29.53 in.Hg, 100.0 kPa)
W - El ‘: :g L ;I 4
: No trouble (“CHECK ENGINE” warning light off) and
engine running.
1
*3A/C - El .,. . :.llC 1~14 Air conditioning ON
>-
T - El 4A.6
Check connector T(TE1) - El not short
Ignition S/W ON
0 Check connector TfTEl) - El short
*3NSW (A/T) - El
*3N/C Uvl/TI -
El 0
Shift position P or N range
Ignition S/W ON
IO-14 Ex. P or N range
0: Clutch pedal not depressed
- Ignition S/W ON .
IO-14 Clutch pedal depressed
..-
I 1044 1 1 Defogger S/W OFF
I
“3DFG - El
“3LP - El 0
10 - 14
j) ‘. Ignition S/W ON
Defogger S/W ON
Headlight S/W OFF
Headlight S/W ON
*I 7M-GE only
*2 7M-GTE only
*3 MA only