
ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTION
lEngine: Return to the original trouble
condition
lChange the amount of fuel injection
using CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lHarness and connectorlFuel injectorslHeated oxygen sensor
IACV-AAC/V
OPENING
lEngine: After warming up, idle the
engine.
lChange the IACV-AAC valve opening
percent using CONSULT.Engine speed changes according to the
opening percent.lHarness and connectorlIACV-AAC valve
ENG COOLANT
TEMP
lEngine: Return to the original trouble
condition
lChange the engine coolant
temperature using CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lHarness and connectorlEngine coolant temperature sensorlFuel injectors
IGNITION TIMING
lEngine: Return to the original trouble
condition
lTiming light: SetlRetard the ignition timing using
CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lAdjust ignition timing (by moving
camshaft position sensor)
POWER BALANCE
lEngine: After warming up, idle the
engine.
lA/C switch ``OFF''lShift lever ``N''lCut off each injector signal one at a
time using CONSULT.Engine runs rough or dies.
lHarness and connectorlCompressionlInjectorslIgnition coil with power transistorlSpark plugs
FUEL PUMP RELAY
lIgnition switch: ON (Engine stopped)lTurn the fuel pump relay ``ON'' and
``OFF'' using CONSULT and listen to
operating sound.Fuel pump relay makes the operating
sound.lHarness and connectorlFuel pump relay
EGRC SOLENOID
VALVE
(EVAP canister
purge control
solenoid valve)
lIgnition switch: ONlTurn solenoid valve ``ON'' and ``OFF''
with CONSULT and listen to
operating sound.Solenoid valve makes an operating
sound.lHarness and connectorlEVAP canister purge control solenoid
valve
SWIRL CONT SOL
VALVE
lIgnition switch: ON (Engine stopped)lTurn solenoid valve ``ON'' and ``OFF''
with CONSULT and listen to
operating sound.Solenoid valve makes an operating
sound.lHarness and connectorlSwirl control valve control solenoid
valve
SELF-LEARNING
CONT
lIn this test, the coefficient of self-learning control mixture ratio returns to the original coefficient by touching ``CLEAR'' on the
screen.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-50

FUNCTION TEST MODE
FUNCTION TEST
ITEMCONDITION JUDGEMENT CHECK ITEM (REMEDY)
SELF-DIAG
RESULTS
lIgnition switch: ON
(Engine stopped)
lDisplays the results of on board
diagnostic system.Ð Objective system
CLOSED THROTTLE
POSI
lIgnition switch: ON
(Engine stopped)
lThrottle position sensor circuit is
tested when throttle is opened
and closed fully. (``IDLE
POSITION'' is the test item name
for the vehicles in which idle is
selected by throttle position
sensor.)Throttle valve:
openedOFF
lHarness and connector
lThrottle position sensor (Closed
throttle position)
lThrottle position sensor (Closed
throttle position) adjustment
lThrottle linkage
lVerify operation in DATA
MONITOR mode. Throttle valve:
closedON
THROTTLE POSI
SEN CKT
lIgnition switch: ON
(Engine stopped)
lThrottle position sensor circuit is
tested when throttle is opened
and closed fully.Range (Throttle
valve fully opened
Ð Throttle valve
fully closed)More than
3.0V
lHarness and connector
lThrottle position sensor
lThrottle position sensor
adjustment
lThrottle linkage
lVerify operation in DATA
MONITOR mode.
PARK/NEUT POSI
SW CKT
lIgnition switch: ON
(Engine stopped)
lNeutral position switch circuit is
tested when shift lever is
manipulated.Out of N/P
positionsOFF
lHarness and connector
lNeutral position switch
lLinkage adjustment
In N/P positions ON
FUEL PUMP
CIRCUIT
lIgnition switch: ON
(Engine stopped)
lFuel pump circuit is tested by
checking the pulsation in fuel
pressure when fuel tube is
pinched.There is pressure pulsation on
the fuel feed hose.
lHarness and connector
lFuel pump
lFuel pump relay
lFuel filter clogging
lFuel level
EGRC SOL/V
CIRCUIT
(EVAP canister purge
control solenoid valve
circuit)
lIgnition switch: ON
(Engine stopped)
lEVAP canister purge control
solenoid valve circuit is tested by
checking solenoid valve operating
noise.The solenoid valve makes an
operating sound every 3
seconds.lHarness and connector
lEVAP canister purge control
solenoid valve
START SIGNAL
CIRCUIT
lIgnition switch: ON®START
lStart signal circuit is tested when
engine is started by operating the
starter. Battery voltage and water
temperature before cranking, and
average battery voltage, mass air
flow sensor output voltage and
cranking speed during cranking
are displayed.Start signal: OFF®ON
lHarness and connector
lIgnition switch
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-51

FUNCTION TEST
ITEMCONDITION JUDGEMENT CHECK ITEM (REMEDY)
PW/ST SIGNAL
CIRCUIT
lIgnition switch: ON
(Engine running)
lPower steering oil pressure switch
circuit is tested when steering
wheel is rotated fully and then set
to a straight line running position.Locked position ONlHarness and connector
lPower steering oil pressure switch
lPower steering oil pump
Neutral position OFF
SWRL CONT S/V
CIRCUIT
lIgnition switch: ON
(Engine stopped)
lSwirl control valve control sole-
noid valve circuit is tested by
checking solenoid valve operating
sound.The solenoid valve makes an
operating sound every 3 sec-
onds.
lHarness and connector
lSolenoid valve
lSwirl control valve
lVacuum hose
VEHICLE SPEED
SEN CKT
lVehicle speed sensor circuit is
tested when vehicle is running at
a speed of 10 km/h (6 MPH) or
higher.Vehicle speed sensor input
signal is greater than 4 km/h
(2 MPH).lHarness and connector
lVehicle speed sensor
lSpeedometer
IGN TIMING ADJ
lAfter warming up, idle the engine.
lIgnition timing is checked by read-
ing ignition timing with a timing
light and checking whether it
agrees with specifications.The timing light indicates the
same value on the screen.
lAdjust ignition timing (by moving
camshaft position sensor or
distributor)
lCamshaft position sensor drive
mechanism
MIXTURE RATIO
TEST
lAir-fuel ratio feedback circuit
(injection system, ignition system,
vacuum system, etc.) is tested by
examining the heated oxygen
sensor output at 2,000 rpm under
non-loaded state.Heated oxygen sensor
COUNT: More than 5 times
during 10 seconds
lINJECTION SYS (Injector, fuel
pressure regulator, harness or
connector)
lIGNITION SYS (Spark plug,
ignition coil, power transistor
harness or connector)
lVACUUM SYS (Intake air leaks)
lHeated oxygen sensor circuit
lHeated oxygen sensor operation
lFuel pressure high or low
lMass air flow sensor
POWER BALANCE
lAfter warming up, idle the engine.
lInjector operation of each cylinder
is stopped one after another, and
resultant change in engine rota-
tion is examined to evaluate com-
bustion of each cylinder. (This is
only displayed for models where a
sequential multiport fuel injection
system is used.)Difference in engine speed is
greater than 25 rpm before
and after cutting off the injec-
tor of each cylinder.lInjector circuit (Injector, harness
or connector)
lIgnition circuit (Spark plug, igni-
tion coil, power transistor harness
or connector)
lCompression
lValve timing
IACV-AAC/V
SYSTEM
lAfter warming up, idle the engine.
lIACV-AAC valve system is tested
by detecting change in engine
speed when IACV-AAC valve
opening is changed to 0%, 20%
and 80%.Difference in engine speed is
greater than 150 rpm between
when valve opening is at 80%
and at 20%.
lHarness and connector
lIACV-AAC valve
lAir passage restriction between
air inlet and IACV-AAC valve
lIAS (Idle adjusting screw) adjust-
ment
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-52

Introduction
The engine has an ECM to control major systems such as fuel
control, ignition control, idle air control system, etc. The ECM
accepts input signals from sensors and instantly drives actua-
tors. It is essential that both input and output signals are proper
and stable. At the same time, it is important that there are no
problems such as vacuum leaks, fouled spark plugs, or other
problems with the engine.
It is much more difficult to diagnose a problem that occurs inter-
mittently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A
road test with CONSULT or a circuit tester connected should be
performed. Follow the ``Work Flow'' on EC-56.
Before undertaking actual checks, take just a few minutes to talk
with a customer who approaches with a driveability complaint.
The customer can supply good information about such problems,
especially intermittent ones. Find out what symptoms are present
and under what conditions they occur. A ``Diagnostic Worksheet''
like the example on next page should be used.
Start your diagnosis by looking for ``conventional'' problems first.
This will help troubleshoot driveability problems on an electroni-
cally controlled engine vehicle.
Diagnostic Worksheet
There are many operating conditions that lead to the malfunc-
tions of engine components. A good knowledge of such condi-
tions can make troubleshooting faster and more accurate.
In general, each customer may feel differently about a given
problem. It is important to fully understand the symptoms or
conditions for a customer complaint.
Utilize a diagnostic worksheet like the one on next page in order
to organize all the information for troubleshooting.
MEF036D
SEF233G
SEF234G
SEF907L
TROUBLE DIAGNOSIS Ð IntroductionKA
EC-54

Basic Inspection
Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
lHeadlamp switch is OFF,
lAir conditioner switch is OFF,
lRear window defogger switch is OFF,
lSteering wheel is in the straight-ahead position, etc.
BEFORE STARTING
1. Check service records for any recent
repairs that may indicate a related
problem, or the current need for sched-
uled maintenance.
2. Open engine hood and check the fol-
lowing:
lHarness connectors for improper con-
nections
lVacuum hoses for splits, kinks, or
improper connections
lWiring for improper connections,
pinches, or cuts
CONNECT CONSULT TO THE
VEHICLE.
Connect ``CONSULT'' to the data link
connector for CONSULT and select
``ENGINE'' from the menu. Refer to
EC-45.
CHECK IGNITION TIMING.
1. Warm up engine sufficiently.
2. Select ``IGN TIMING ADJ'' in
``WORK SUPPORT'' mode.
3. Touch ``START''.
4. Check ignition timing at idle
using timing light.
Ignition timing:
10É 2É BTDC
----------------------------------------------------------------------------------------------------------------------------------OR----------------------------------------------------------------------------------------------------------------------------------
1. Warm up engine sufficiently.
2. Stop engine and disconnect
throttle position sensor sub-
harness connector.
3. Start engine.
4. Check ignition timing at idle
using timing light.
Ignition timing:
10É 2É BTDC
OK
cNG
Adjust ignition timing by
turning camshaft position
sensor.
VA
(Go to next page.)
SEF142I
SEF056UA
SEF555N
SEF148U
SEF284G
.
.
.
TROUBLE DIAGNOSIS Ð Basic InspectionKA
EC-58

VA
CHECK IDLE SPEED ADJ.
SCREW INITIAL SET RPM (BASE
IDLE SPEED).
1. Select ``IGN TIMING
ADJ'' in ``WORK SUP-
PORT'' mode.
2. When touching
``START'', does engine
speed fall to 750 25
rpm?
-----------------------------------------------------------------------------------------------------------OR -----------------------------------------------------------------------------------------------------------
When disconnecting throttle
position sensor sub-har-
ness connector, does
engine run at 750 25 rpm?
OK
cNG
Adjust base idle speed by turning
idle speed adjusting screw.
CHECK THROTTLE POSITION
SENSOR IDLE POSITION.
1. Perform ``THRTL POS
SEN ADJ'' in ``WORK
SUPPORT'' mode.
2. Check output voltage of
throttle position sensor.
Voltage: 0.35 - 0.65V
-----------------------------------------------------------------------------------------------------------OR -----------------------------------------------------------------------------------------------------------
1. Reconnect throttle posi-
tion sensor sub-harness
connector.
2. Check output voltage
between throttle position
sensor terminal
V2and
ground with voltmeter.
Voltage: 0.35 - 0.65V
OK
cNG
Adjust output voltage to 0.5V by
rotating throttle position sensor
body.
RESET IDLE POSITION
MEMORY.
1. Disconnect throttle position
sensor sub-harness connector.
2. Warm up engine sufficiently.
3. Select ``CLSD THL/
POSI'' in ``DATA MONI-
TOR'' mode (Manual
trigger) with CONSULT,
then stop engine.
4. Reconnect throttle position
sensor sub-harness connector.
5. Start engine and wait for a few
seconds.
6. Turn ignition switch ``OFF'' and
wait at least 5 seconds.
7.
Repeat steps 5. and 6.
until ``CLSD THL/POSI''
in ``DATA MONITOR''
mode with CONSULT
changes to ``ON''.
Repeat steps 5. and 6.
10 times.
b
VB
(Go to next page.)
SEF546N
SEF149U
.
.
.
.
TROUBLE DIAGNOSIS Ð Basic InspectionKA
Basic Inspection (Cont'd)
EC-59

Fail-Safe Chart
The ECM enters fail-safe mode, if any of the following malfunctions are detected due to the open or short
circuit.
When the ECM enters the ECM fail-safe mode listed in the last column below, the MIL illuminates.
DTC No.Detected
itemsEngine operating condition in fail-safe mode
12Mass air
flow sensor
circuitEngine speed will not rise more than 2,400 rpm due to the fuel cut.
13 Engine cool-
ant tempera-
ture sensor
circuitEngine coolant temperature will be determined by ECM based on the time after turning ignition switch
``ON'' or ``START''.
CONSULT displays the engine coolant temperature decided by ECM.
41 Intake air
temperature
sensor cir-
cuitThe ECM controls on the assumption that the intake air temperature is 20ÉC (68ÉF).
43 Throttle
position sen-
sor circuitThrottle position will be determined based on the amount of mass air flow and the engine speed.
Therefore, acceleration will be poor.
Unable to
access Diag-
nostic Test
Mode IIECMECM fail-safe activating condition
The computing function of the ECM was judged to be malfunctioning.
When the fail-safe system activates, i.e. if the ECM detects a malfunction condition in the CPU of
ECM, the MALFUNCTION INDICATOR LAMP on the instrument panel lights to warn the driver.
However, it is not possible to access ECCS and DTC cannot be confirmed.
Engine control with ECM fail-safe
When the fail-safe system is operating, fuel injection, ignition timing, fuel pump operation and IACV-
AAC valve operation are controlled under certain limitations.
Replace ECM, if ECM fail-safe condition is confirmed.
ConditionEngine coolant temperature decided
(CONSULT display)
Just as ignition switch is turned ON or START 20ÉC (68ÉF)
More than 6 minutes after ignition START 80ÉC (176ÉF)
Except as shown above20 - 80ÉC (68 - 176ÉF)
(Depends on the time)
Driving condition
When engine is idling Normal
When accelerating Poor acceleration
ECM fail-safe operation
Engine speed Engine speed will not rise more than 3,000 rpm.
Fuel injection Simultaneous multiport fuel injection system
Ignition timing Ignition timing is fixed at the preset value.
Fuel pumpFuel pump relay is ``ON'' when engine is running and ``OFF'' when
engine stalls.
IACV-AAC valve Full open
TROUBLE DIAGNOSIS Ð General DescriptionKA
EC-61

Symptom Matrix Chart
SYMPTOM
Reference page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
OVERCOOLS
OVERCHARGING
Warranty Symptom Code AA AB AC AD AE AF AG AH AJ AK AL AM HA 1P 1X
Basic engine control system
Fuel Fuel pump circuitllljlljjjEC-151
Fuel pressure regulator system
llljljlljlEC-22
Injector circuit
llljlll lEC-144
Evaporative emission systemjjjj
ljjjj jEC-19
Air Positive crankcase ventilation systemjjjj
ljjjj jjEC-21
Incorrect idle speed adjustmentjj jjjj jEC-25
Swirl control valve circuitjj
lEC-161
IACV-AAC valve circuit
llljllllljjEC-131
IACV-FICD solenoid valve circuitjjjjjjjjj jEC-168
Ignition Incorrect ignition timing adjustmentjj
lll ll lEC-25
Ignition circuit
lllll ll lEC-99
EVAP EVAP canister purge control solenoid
valve circuit
ljjjj j jEC-140
Main power supply and ground circuit
llljj jj jj jEC-75
Air conditioner circuitjjjjjjjjj j jHA section
ECCS system
ECCS Camshaft position sensor circuitllllljj jEC-82
Mass air flow sensor circuit
lllll ljjEC-89
Heated oxygen sensor circuit
lljlljlEC-123, 127
Engine coolant temperature sensor circuit
llljllljjlEC-95
Throttle position sensor circuit
ll lllll lEC-113
Incorrect throttle position sensor adjust-
ment
ljjljjljEC-58
Vehicle speed sensor circuitjj j jEC-118
ECMjjjjjjjjjjjEC-61
Start signal circuitjEC-149
Neutral position switch circuitjjjj jEC-136
Power steering oil pressure switch circuitjjjEC-157
l; High Possibility Item
j; Low Possibility Item(continued on next page)
TROUBLE DIAGNOSIS Ð General DescriptionKA
EC-62