Page 774 of 1701

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION
CONSULT (Conl'd)
FUNCTION TEST
CONDITION JUDGEMENT
ITEM CHECK
ITEM(REMEDY)
• Ignition switch:ON
COOLING FAN (Engine
stopped)
Thecooling fanrotates andstops every •
Harness andconnector
CIRCUIT •
Cooling fancircuit is
3seconds. •
Cooling fanmotor
tested whencooling fanis
•Cooling fanrelay
rotated .
• Ignition switch:ON-.
START
• Start signal circuit is
tested whenengine is
started byoperating the
starter. Beforecranking,
START SIGNAL batteryvoltage andengine
Startsignal: OFF-.ON •
Harness andconnector
CIRCUIT coolanttemperature are •
Ignition switch
displayed. During
cranking, averagebattery
voltage, massairflow
sensor outputvoltage and
cranking speedaredis-
played .
• Ignition switch:ON
(Engine running)
Lockedposition ON
•Harness andconnector
PW/ST SIGNAL •
Power steering circuitis
•Power steering oilpres-
tested whensteering
CIRCUIT wheelisrotated fullyand sure
switch
then settoastraight lineNeutral
position OFF•
Power steering pump
running position.
• Vehicle speedsensor cir-
•Harness andconnector
VEHICLE SPEED cuit
istested whenvehicle Vehicle
speedsensor inputsignal is
•Vehicle speedsensor
SEN CKT is
running ataspeed of10 greater
than4km/h (2MPH)
•Electric speedometer
km/h (6MPH) orhigher .
• After warming up,idle the
engine. •Adjust ignition timing(by
• Ignition timingadjustment
movingcamshaft position
IGN TIMING ADJ is
checked byreading The
timing lightindicates thesame
sensorordistributor)
ignition timingwithatim- value
onthe screen.
•Camshaft positionsensor
ing light andchecking
drivemechanism
whether itagrees with
specifications.
•INJECTION SYS(Injector,
fuel pressure regulator,
harness orconnector)
• Air-fuel ratiofeedback cir- •
IGNITION SYS(Spark
cuit (injection system,igni- plug,
power transistor,
tion system, vacuum ignition
coil,harness or
MIXTURE RATIO system,
etc.)istested byOxygen
sensor'1 COUNT:Morethan5 connector)
TEST examining
theoxygen times
during 10seconds •
VACUUM SYS(Intake air
sensor'1 outputat2,000 leaks)
rpm under non-loaded •
Oxygen sensor'1 circuit
state. •
Oxygen sensor'1 opera-
tion
• Fuel pressure highorlow
• Mass airflow sensor
'1: Heated oxygen sensor(ForEurope andIsrael, andAustralia AITmodels)
Oxygen sensor(Except forEurope andIsrael, andAustralia
A/T
models)
EC-55
•
Page 775 of 1701

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION
CONSULT (Cont'd)
FUNCTION TEST
CONDITION JUDGEMENTCHECKITEM(REMEDY)
ITEM
•After warming up,idle the
engine .
• Injector operation ofeach •Injector circuit(Injector,
cylinder isstopped one harnessorconnector)
after another, andresult-
Difference inengine speedisgreater •
Ignition circuit(Spark
POWER BALANCE ant
change inengine rota-
than25rpm before andafter cutting off plug,
power transistor,
lion isexamined toevalu-
theinjector ofeach cylinder. ignition
coil,harness or
ate combustion ofeach connector)
cylinder. (Thisisonly dis- •Compression
played formodels wherea •
Valve timing
sequential multiportfuel
injection systemisused.)
• After warming up,idle the
•Harness andconnector
engine. •IACV-AAC valve
• IACV-AAC valvesystem is
Difference inengine speedisgreater •
Air passage restriction
IACV-AACIV testedbydetecting change
than150rpm between whenvalveopen- betweenairinlet and
SYSTEM inengine speedwhen
ingisat 80% andat20%. IACV-AACvalve
IACV-AAC valveopening
•IAS (Idle adjusting screw)
is changed to0%, 20%
and 80%. adjustment
EC-56
Page 832 of 1701

TROUBLEDIAGNOSIS FORDTC21
Malfunction isdetected when...
Diagnostic
Trouble
Code No.
Ignition
coil
&
power
transistor harnessconnectors
AEC832 Ignition
Signal
COMPONENT DESCRIPTION
Ignition coil
&
power transistor (Builtintodistributor)
The ignition coilisbuilt intodistributor. Theignition signalfrom
the ECM issent tothe power transistor. Thepower transistor
switches onand offthe ignition coilprimary circuit.Asthe pri-
mary circuit isturned onand off,the proper highvoltage is
induced inthe coil secondary circuit.
Check Items
(Possible Cause)
•
21
•
The ignition signalinthe primary circuitisnot
entered toECM during engine cranking orrunning. •
Harness orconnectors
(The ignition primary circuitisopen orshorted.)
• Power transistor unit.
• Resistor
• Camshaft positionsensor
• Camshaft positionsensorcircuit
DIAGNOSTIC TROUBLECODECONFIRMATION
PROCEDURE
Note: Ifboth DTC11and 21are displayed, performTROUBLE
DIAGNOSIS FORDTC11first. Refer toEC-94.
(F.i\ 1)Turn ignition switch"ON".
~ 2)Select "DATA MONITOR" modewithCONSULT.
3) Start engine.
----------OR ----------
1) Turn ignition switch"ON".
2) Start engine.
3) Turn ignition switch"OFF", waitforatleast 5seconds
and then turn"ON".
4) Perform "Diagnostic TestMode II"(Self-diagnostic
results) withECM.
EC-113
Page 835 of 1701

Repairharness orcon-
nectors.
Check
thefollowing.
• Harness connectors
QD,@orGD.
@
• Harness connectors
@.
• Harness foropen or
short between ignition
coil and ignition switch
If
NG, repair harness or
connectors.
Repair harness orcon-
nectors.
NG Yes
NG
NG
CHECK
GROUND CIRCUIT.
1. Turn ignition switch"OFF".
2. Disconnect powertransistor harness
connector.
3. Check harness continuity between
terminal
@
and engine ground.
Continuity shouldexist.
If OK, check harness forshort.
OK OK
INSPECTION
START
Turn ignition switch"OFF", andrestart
engine.
Is engine running?
No
CHECK POWER SUPPLV.
1. Turn ignition switch"OFF".
2. Disconnect ignitioncoilharness con-
nector.
3. Turn ignition switch"ON".
4. Check voltage between terminal
(J)
and ground withCONSULT ortester.
Voltage: Balteryvoltage
CHECK INPUTSIGNAL CIRCUIT.
1. Disconnect ECMharness connector.
2. Check harness continuity between
ECM terminal
G)
and power transis-
tor terminal
G).
Continuity shouldexist.
If
OK, check harness forshort.
AEC832
SEF468Q
TROUBLE
DIAGNOSIS FORDTC21
Ignition Signal(Cont'd)
DIAGNOSTIC PROCEDURE
SEF469Q
~15
@3
ill~
~85 ~85
II
ECM
~CONNECTORII
(tI2IffllsI6)
1 OK
CHECK COMPONENTS
(Ignition coil,power transistor).
Refer to"COMPONENT INSPECTION",
EC-118. NG
Replace malfunctioning
component(s).
OK •
Disconnect andreconnect harnesscon-
nectors inthe circuit. Thenretest.
SEF470Q
Troubleisnot fixed.
Check ECMpinterminals fordamage
or the connection ofECM harness con-
nector. Reconnect ECMharness con-
nector andretest.
INSPECTION END
EC-116
Page 836 of 1701
•
Repair
harness orcon-
nectors.
(;J
CHECK INPUTSIGNAL CIRCUIT. NG
1. Stop engine.
2. Disconnect ignitioncoilharness con-
nector.
3. Strip tapecovering resistoranddis-
connect theconnector.
4. Disconnect ECMharness connector.
5. Check harness continuity between
ignition coilterminal
@
and resistor
terminal
(!),
resistor terminal
@
and ECM terminal
@
or
@.
Continuity shouldexist.
If OK, check harness forshort.
TROUBLE
DIAGNOSIS FORDTC21
Ignition Signal(Cont'd)
@
~io
cffiJ
~i8
dIb
OK
~i5
1=1
=E=CM====!:E'
CONNECTOR
II
3
CHECK
COMPONENTS
(Resistor).
Refer to"COMPONENT INSPECTION"
on next page.
Disconnect andreconnect harnesscon-
nectors inthe circuit. Thenretest.
NG
Replace resistor.
Trouble isnot fixed.
@3)
CD:
For Australia
@ :Except forAustralia
SEF143R
Check
ECMpinterminals fordamage
or the connection ofECM harness con-
nector. Reconnect ECMharness con-
nector andretest.
INSPECTION END
EC-117
Page 837 of 1701

TROUBLEDIAGNOSIS FORDTC21
Ignition Signal
(Cont'd)
COMPONENT INSPECTION
Ignition coil
1. Disconnect ignitioncoilharness connector.
2. Check resistance asshown inthe figure.
If NG, replace ignitioncoil.
3. For checking secondary coil,remove distributor cap.
4. Check resistance betweenignitioncoilharness connector
terminal
q)
and thesecondary terminalonthe distributor
head. If NG, replace distributor.
Terminal
(j) -
CID
(Primary coil)
(j) -
secondary terminalondistrib-
utor head (Secondary coil) Resistance
[at25°C
(7rF))
Approximately 1Q
Approximately 10kQ
Power transistor
terminals ~
.B..
(615143121D
(~l..?)
SEF473Q
AEC841 Power
transistor
1. Disconnect powertransistor harnessconnector.
2. Check powertransistor resistance betweenterminals
@
and
@.
Terminals Resistance Result
NotOQ
OK
@
and
CID
OQ NG
If NG, replace distributor.
Resistor
1. Disconnect resistorharness connector.
2. Check resistance betweenterminals
CD
and
@.
Resistance: Approximately 2.2kQ[at25°C (77°F)]
If NG, replace resistor.
EC-118
Page 862 of 1701

•
INSPECTION END
Check thefollowing.
• Harness connectors
@,@or@,
@
• Harness connectors
@,CillD
• Harness foropen or
short between injector
and ignition switch
If NG, repair harness or
connectors.
OK
NG
DIAGNOSTIC
PROCEDURE
INSPECTION START
CHECK OVERALL FUNCTION.
(F.I\
1.Start engine.
~ 2.Perform "POWER BALANCE"
in "ACTIVE TEST"modewith
CONSULT.
3. Make surethateach circuit
produces amomentary engine
speed drop.
OR
fff\
1.Start engine.
~ 2.Listen toeach injector operat-
ing sound.
Clicking noiseshould be
heard.
CHECK POWER SUPPLY.
1. Stop engine.
2. Disconnect injectorharness connec-
tor.
3. Turn ignition switch"ON".
4. Check voltage between terminal @
and ground withCONSULT ortester.
Voltage: Batteryvoltage
AEC872
SEF730L
/~~
Click
Ct.
'~.+
Fuel injector harness
connector
II
TROUBLE
DIAGNOSIS FORNON-DETECTABLE ITEMS
Injector (Cont'd)
COMPONENT DESCRIPTION
The fuel injector isasmall, precise solenoid valve.Whenthe
ECM supplies aground tothe injector circuit,thecoil
in
the
injector isenergized. Theenergized coilpulls theneedle valve
back andallows fueltoflow through theinjector intotheintake
manifold. Theamount offuel injected depends upontheinjec-
tion pulse duration. Pulseduration isthe length oftime the
injector remains open.TheECM controls theinjection pulse
duration basedonengine fuelneeds.
SEF596K
• ACTIVE TEST.
D
••• POWER BALANCE •••
= ==
MONITOR
=
==
CMPS.RPM(REF) 737rpm
MAS AIR/FL SEN098V
IACV-AAC/V 41%
110Q]Q]~
DDDDc:J
MEF354F
~7~
~ \)drJ
At idle
--
/ I
AEC755EC-143
Page 890 of 1701

•
INSPECTION END
OK
The
power steering oilpressure switchisattached tothe power
steering high-pressure tubeanddetects apower steering load.
When apower steering loadisdetected,
it
signals theECM. The
ECM adjusts theIACV-AAC valvetoincrease theidle speed and
adjust forthe increased load.
INSPECTION START
OR
1. Start engine.
2. Check voltage between ECM
terminal
@
or
@
and ground.
Voltage: When steering wheelis
turned quickly.
Approximately OV
Except above
Approximately 5V
NG
DIAGNOSTIC
PROCEDURE
CHECK OVERALL FUNCTION.
fiii\
1.Turn ignition switch"ON".
~ 2.Perform "PW/STSIGNAL
CIRCUIT" in"FUNCTION
TEST" modewithCONSULT.
OR
(F.i\
1.Start engine.
~ 2.Check "PW/ST SIGNAL" in
"DATA MONITOR" modewith
CONSULT.
Steering isin neutral
position: OFF
Steering isturned:
ON
SEF591I
SEF235R
MEF023E
Power
steering oil___
pressure switch
-
~
to
TROUBLE
DIAGNOSIS FORNON-DETECTABLE ITEMS
@[]
Power Steering OilPressure Switch(Cont'd)
COMPONENT DESCRIPTION
RECORD
NEXT
II
START
•
PW/ST SIGNAL CIRCUIT.
HOLD STEERING WHEEL
IN AFULL
LOCKED
POSITION
THEN
TOUCH START
* MONITOR *NO FAIL
0
PW/ST SIGNAL OFF
@):
ForAustralia
@:
Except forAustralia
~i)~
II
ECM
Ef
CONNECTOR
II
43 25
EC-171