Check wiring between ECU terminal E1 and body ground.!. oO | Voltmeter = Check starter OK | Check wiring between ECU terminal STA Repair or replace.. Foci tr I+roTrpn ay Check fusible
Trang 1EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE) FI-41
Ignition switch Coolant temperature 80°C
ECU
Water Temp Sensor +B (+B1)
———TT”]
THW
~ FIO487
đ) ® There is no voltage between ECU terminals THW and E2
body ground (IG SW ON)
Refer to No 1
!
Check wiring between ECU terminal E1 and body ground
FI3646
Trang 2
EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE)
FI-42
To Circuit Opening Relay (STA)
O- OSTA
AM1 40A
M/T
(USA A/T)| Switen (wim)
Link
MAIN 2.0L
Starter Starter Relay
Battery| ,_-
đ) ® There is no voltage between ECU terminals STA and E1
oO |
Voltmeter = Check starter OK | Check wiring between ECU terminal STA
Repair or replace
FIO335
ground
Foci tr I+roTrpn
ay
Check fusible links, battery, wiring,
Ignition switch and neutral start =| Repair or replace switch
Voltmeter
Starter Terminal 50 ® Check that there is voltage at terminal 50 of starter
(IG SW START) STD voltage: 6—14V
Ỉ
Check wiring between ignition switch Check starter terminal ST1 and starter terminal 50
FIO336
Trang 3
EFl SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE) FI-43
ECU Ignition Switch
To
MAIN 2.0L
_?
—_
IGT
= ¬ FI3579
(1) ® There is no voltage between ECU terminals IGT and E1
(Idling)
OOO QOOQ0O0U0 DODOOOO000
Voltmeter | (== ee ® Check that there is voltage between ECU terminal IGT and body
Check wiring between ECU BAD Repair or
FI1642
terminal E1 and body ground replace
Voltmeter DDDE lieisisisieis.s DDDDBEDOOrc
!
switch
Check distributor (See page IG-9) =| Repair or replace
OK
battery
OK
ley te—
BAD
FIO311
Trang 4FI-44 EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE)
Fuse
-ẳ5-
EFI 15A Fusible
Fusible
Link MAIN 2.0L
Battery
rt
7 ¬ FIS659
ISC1 ISC2 q)
—
LILLILJL) LILJLILIE]LCILIDIE]
LIUJLILILILRH—)L)LILILICICIEI1DIDIE›
Voltmeter {|}
V +o
FI4899
Voltmeter
TL re
FIO312
®
Battery
©
FI1643
E1 (IG SW ON)
® There is no voltage between ECU terminals ISC1 ~ ISC4 and
® Check that there is voltage between ECU terminal +B (+B1)
and body ground (IG SW ON)
OK
!
NO
Refer to No 1
(See page F 1-35)
Check wiring between ECU terminal E1 and body ground
OK
Check ISC valve
@ (See page FI-106)
†
BAD
Repair or replace
OK
!
Replace ISC valve
Check wiring between ECU and EFI
Try another ECU
Trang 5
EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE) FI-45
10 W — E1 No voltage No trouble ( CHECK ENGINE” warning light 8_— 14V
off) and engine running
ECU
_
Warning Light
Combination Meter
FIO728
đ) ® There is no voltage between ECU terminals W and E1
(Idling)
Check that there is voltage between ECU terminal W and body
+o
FI1250
Ohmmeter
fe ec a Pl ce
FIO311
|
Check GAUGE fuse (7.5A) and “CHECK
| Repair or replace
Fuse blows again
|
Ta
terminal W and fuse
Trang 6
Fl-46 EFl SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE)
ECU
{| E1
FI4925
® a) There is no voltage between ECU terminals A/C and E1
(Air conditioning ON)
y
® Check that there is voltage between ECU terminal A/C and
ground
FI1255
Voltmeter
Check that there is voltage between BAD amplifier terminal and body ground
| OK
Check wiring between amplifier and BAD
54 ECU terminal A/C
- Repair or replace
~ Repair or replace
Oh
L =
5BDID[DBB 1IZJBBS10202101
m m ete r i H
XÍ Nig
SỐ A \\
FIO311
Trang 7
EFl SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE) FI-47
California vehicles only
ECU
Check Connector
Oxygen Sensor
Sub-Oxygen Sensor 4
—- —-— Sr
E1
—
FI3383
DGDEN32DDDDDCLI2ODODLIDDDDO .= -D@DDODDDEI2DDIGOCOOIOUOUDOEC
FI2947
, 0 0= TP
+
aa
Fl4210
| There is no voltage between ECU terminals VF1 and E1 4
Check that there is specified voltage between ECU terminal VF1 and body ground
| Check wiring between ECU terminal E1 and body ground |
Check for suction of air into exhaust BAD Repair air suction
| OK
L Check for air leak from air intake system Repair air leak
_†OK
_EOK
| OK
' OK
B
B
B
B
B
| PAR
Pee
! Check distributor and ignition system —= Repair or replace
=f
| Check cold start injector *
Repair or replace
1 OK
AD
AD
AD
AD
AD
AD
|@ Check operation of oxygen sensors -—-—4 System normal
1 BAD
Check wiring between oxygen sensors BAD
| OK
i Replace oxygen sensors ï ” Rich malfunction only
Trang 8
FI-48 EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GE)
California vehicles only
EGR Gas Temp Sensor EGR
Valve
ECU
+B (+B1)
THG
A
“J
FI2680
Voltmeter
O)
FI2945
There is voltage between ECU terminals THG and E2
œ@ (IG SW ON)
!
® Check that there is voltage between ECU terminal +B(+B1) and
body ground (IG SW ON)
(2)
+B1
Voltmeter
FIO312
OK
!
NO
Refer to No 1 (See page F 1-35)
Check wiring between ECU terminal E1 and body ground
OK
†
l BAD
Repair or replace
FI2674
BAD Check EGR system
OK
y
Check EGR gas temp sensor
(See page Fl-118)
Repair or replace
Replace EGR gas temp
Check wiring between ECU and EGR gas temp sensor
OK
Ƒ
| BAD
Repair or replace
Trang 9
EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GTE) FI-49
TROUBLESHOOTING WITH VOLT/OHMMETER (7M-GTE) HINT: The following troubleshooting procedures
are designed for inspection of each separate sys-
tem, therefore the procedure may vary somewhat
However, troubleshooting should be performed
referring 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 con-
dition of the connectors
The following troubleshooting procedures are based
on the supposition that the trouble lies in either a short or open circuit in a component outside the computer or a short circuit within the computer
If engine trouble occurs even though proper oper- ating voltage is detected in the computer connec- tor, then it can be assumed the computer is faulty and should be replaced
LOCATION OF FUSES AND FUSIBLE LINKS
Fusible Link
No 2
GAUGE 7.5A OO
ALT 100A
No 1 Junction Block
Fusible Link AM140A
EFI Main Relay
Junction Block
TỔ
Z2
AS
is
]
Fusible Link Fuse
Trang 10FI-50 EFI SYSTEM — Troubleshooting with Volt/Ohmmeter (7M-GTE)
“A”
——
SF; Lock
= LS OC
HE Ver SS CM
FI2944
Voltmeter
©)
ECU
+B
FI2911
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
NOTICE: Pay attention to sections ““A““ and ““B““ in the illustration which can be easily broken
(c) Reconnect the connectors to the ECU
HINT:
e Perform all voltage measurements with the connectors connected
e Verify that the battery voltage is 11 V or more when the ignition switch is in ‘‘ON”’ position
Using a voltmeter with high impedance (10 kQ/V minimum), measure the voltage at each terminal of the wiring con-
nectors
Terminals of ECU
E01 | POWER GROUND G2 CAM POSITION SENSOR A/C | A/C COMPRESSOR
EO2 | POWER GROUND G1 CAM POSITION SENSOR *2 LP HEADLIGHT RELAY
No 10 | INJECTOR (No 1 and 6) NE | CAM POSITION SENSOR SPD | SPEED SENSOR
No 30 | INJECTOR (No 4 and 5) E1 COMPUTER GROUND *3ECT | ECT COMPUTER
No 20 | INJECTOR (No 2 and 3) VF | CHECK CONNECTOR *2DFG | DEFOGGER RELAY
STJ | COLD START INJECTOR GO | CAM POSITION SENSOR L1 TEMS COMPUTER
HT | OXYGEN SENSOR HEATER OIL | OIL PRESSURE SWITCH FC CIRCUIT OPENING RELAY
— — TE1 | CHECK CONNECTOR L2 TEMS ECU COMPUTER
VSV2_ | VSV (FPU) OX | OXYGEN SENSOR FP FUEL PUMP RELAY
— — — — L3 TEMS COMPUTER
EGR | VSV (EGR) KNK1 | KNOCK SENSOR W WARNING LIGHT
— — KNK2 | KNOCK SENSOR Tit | TURBO INDICATOR
ISC1_ | ISC MOTOR NO 1 COIL THW | WATER TEMP SENSOR M-REL | EFl MAIN RELAY (COIL)
IGT | IGNITER IDL | THROTTLE POSITION SENSOR — —
ISC2 | !SC MOTOR NO 2 COIL THA_ | AIR TEMP SENSOR — —
IGDA | IGNITER VTA | THROTTLE POSITION SENSOR — —
ISC3_ | ISC MOTOR NO 3 COIL KS AIR FLOW METER |GSW_ | IGNITION SWITCH
IGDB | IGNITER — — +B1_ | EFl MAIN RELAY
— — E2 SENSOR GROUND +B EFI MAIN RELAY
IGF | IGNITER STA | STARTER SWITCH *1 California vehicles only
*ITHG | EGR GAS TEMP SENSOR (nsw) | NEUTRAL START SWITCH (A/T) AIT only
ECU Terminals
E01] NO-}NO-T ut |¥2¥eGr SOT Se 'S5 | Slice] G2 [Ne] | vF foi] ox |KKIHWTHA| Ks |vc| BTAlA/c|sPplDrdl rc | FP | W \Ney} — | ay PATY
feo2|\°-Ists| — | — | — J\eTrleoAlsoal - |rHQ G1 E1Í |6 ©|lrEt| - |“ề*libLVTA| — |E2 | [6| LP JECT| L |L2 | L3 |riL| — | — [+81] +B]
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