6-1-24 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
ConditionPossible CauseReferring Item
OverheatingInoperative thermostat
Poor water pump performance
Clogged or leaky radiator
Improper engine oil grade
Clogged oil filter or oil strainer
Poor oil pump performance
Faulty radiator fan control system
Dragging brakes
Slipping clutch
Blown cylinder head gasketThermostat in Section 6B
Water pump in Section 6B
Radiator in Section 6B
Engine oil and oil filter change in
Section 0B
Oil pressure check in Section 6A1
Oil pressure check in Section 6A1
Radiator fan control system in
Section 6E2
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Cylinder head in Section 6A1
Poor gasoline
mileageIgnition system out of order
Leaks or loose connection of high-tension cord
Faulty spark plug (improper gap, heavy deposits
and burned electrodes, etc.)
Engine and emission control system out of
order
Malfunctioning EGR valve
High idle speed
Poor performance of TP sensor, ECT sensor or
MAP sensor
Faulty EGR valve
Faulty fuel injector(s)
Faulty ECM (PCM)
Low compression
Others
Poor valve seating
Dragging brakes
Slipping clutch
Thermostat out of order
Improper tire pressure
High-tension cords in Section 6F1
Spark plugs in Section 6F1
EGR system in Section 6E2
Refer to item “Improper engine
idle speed” previously outlined
TP sensor, ECT sensor or MAP
sensor in Section 6E2
EGR system in Section 6E2
Diagnostic Flow Table B-1
Previously outlined
Valves inspection in Section 6A1
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Thermostat in Section 6B
Refer to Section 3F
Excessive engine
oil consumptionOil leakage
Blown cylinder head gasket
Leaky camshaft oil seals
Oil entering combustion chamber
Sticky piston ring
Worn piston and cylinder
Worn piston ring groove and ring
Improper location of piston ring gap
Worn or damaged valve stem seal
Worn valve stem
Cylinder head in Section 6A1
Camshaft in Section 6A1
Piston cleaning in Section 6A1
Pistons and cylinders inspection
in Section 6A1
Pistons inspection in Section 6A1
Pistons assembly in Section 6A1
Valves removal and installation in
Section 6A1
Valves inspection in Section 6A1
6-1-28 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
ConditionPossible CauseReferring Item
Excessive
hydrocarbon (HC)
emission or carbon
monoxide (CO)Ignition system out of order
Faulty spark plug
Leaky or disconnected high-tension cord
Faulty ignition coil with ignitor
Low compression
Engine and emission control system out of
order
Lead contamination of three way catalytic
converter
Faulty evaporative emission control system
Fuel pressure out of specification
Closed loop system (A / F feed back
compensation) fails
–Faulty TP sensor
–Poor performance of ECT sensor or MAP
sensor
Faulty injector(s)
Faulty ECM (PCM)
Others
Engine not at normal operating temperature
Clogged air cleaner
Vacuum leaks
Spark plugs in Section 6F1
High-tension cords in Section 6F1
Ignition coil assembly in Section
6F1
Refer to “Low compression”
section
Check for absence of filler neck
restrictor
EVAP control system in Section
6E2
Diagnostic Flow Table B-3
TP sensor in Section 6E2
ECT sensor or MAP sensor in
Section 6E2
Diagnostic Flow Table B-1
Excessive nitrogen
oxides (NOx)
emissionIgnition system out of order
Improper ignition timing
Engine and emission control system out of
order
Lead contamination of catalytic converter
Faulty EGR system
Fuel pressure out of specification
Closed loop system (A / F feed back
compensation) fails
–Faulty TP sensor
–Poor performance of ECT sensor or MAP
sensor
Faulty injector(s)
Faulty ECM (PCM)
See section 6F1
Check for absence of filler neck
restrictor.
EGR system in Section 6E2
Diagnostic Flow Table B-3
TP sensor in Section 6E2
ECT sensor or MAP sensor in
Section 6E2
Diagnostic Flow Table B-1
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-29
SCAN TOOL DATA
As the data values given below are standard values estimated on the basis of values obtained from the normally
operating vehicles by using a scan tool, use them as reference values. Even when the vehicle is in good condition,
there may be cases where the checked value does not fall within each specified data range. Therefore, judgment
as abnormal should not be made by checking with these data alone.
Also, conditions in the below table that can be checked by the scan tool are those detected by ECM (PCM) and
output from ECM (PCM) as commands and there may be cases where the engine or actuator is not operating (in
the condition) as indicated by the scan tool. Be sure to use the timing light to check the ignition timing.
NOTE:
With the generic scan tool, only star () marked data in the table below can be read.
When checking the data with the engine running at idle or racing, be sure to shift M / T gear to the neutral
gear position and A / T gear to the “Park” position and pull the parking brake fully. Also, if nothing or “no
load” is indicated, turn OFF A / C, all electric loads, P / S and all the other necessary switches.
SCAN TOOL DATAVEHICLE CONDITIONNORMAL CONDITION /
REFERENCE VALUES
FUEL SYSTEM B1 (FUEL
SYSTEM STATUS)At specified idle speed after warming upCLOSED
(closed loop)
CALC LOAD
(CALCULATED LOADAt specified idle speed with no load after
warming up3 – 9%(
VALUE)At 2500 r / min with no load after warming up12 – 17%
COOLANT TEMP.
(ENGINE COOLANT
TEMP.)
At specified idle speed after warming up85 – 100C,
185 – 212F
SHORT FT BI (SHORT
TERM FUEL TRIM)At specified idle speed after warming up–20 – +20%
LONG FT BI (LONG
TERM FUEL TRIM)At specified idle speed after warming up–15 – +15%
MAP (INTAKE
MANIFOLD ABSOLUTE
PRESSURE)At specified idle speed with no load after
warming up24 – 37 kPa,
180 – 280 mmHg
ENGINE SPEEDAt idling with no load after warming up
Desired
idle speed
± 50 r / min
VEHICLE SPEEDAt stop0 km / h, 0 MPH
IGNITION ADVANCE
(IGNITION TIMING
ADVANCE FOR NO.1
CYLINDER)
At specified idle speed with no load after
warming up9 – 15 BTDC
INTAKE AIR TEMP.At specified idle speed after warming upAmbient +35C (95F)
temp.–5C (23F)
MAF (MASS AIR FLOW
RATE)
At specified idle speed with no load after
warming up0 – 4 gm / sec
RATE)At 2500 r / min with no load after warming up4 – 9 gm / sec
THROTTLE POS
(ABSOLUTE
Ignition switch
ON / engineThrottle valve fully closed7 – 18%
(ABSOLUTE
THROTTLE POSITION)
ON / engine
stoppedThrottle valve fully open70 – 100%
O2S B1 S1 (HEATED
OXYGEN SENSOR-1)At specified idle speed after warming up0.05 – 0.95 V
O2S B1 S2 (HEATED
OXYGEN SENSOR-2)When engine is running at 2000 r / min. for
3 min or longer after warming up.0 – 0.95 V
O2S FT B1 S1At specified idle speed after warning up–20 – +20%
DIS. WITH MIL ON————
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-31
SCAN TOOL DATA DEFINITIONS
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air / fuel ratio feedback loop status displayed as either
open or closed loop. Open indicates that ECM (PCM)
ignores feedback from the exhaust oxygen sensor.
Closed indicates final injection duration is corrected
for oxygen sensor feedback.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum
possible load. Value is calculated mathematically us-
ing the formula: actual (current) intake air volume
maximum possible intake air volume x 100%.
COOLANT TEMP.
(ENGINE COOLANT TEMPERATURE, C, F)
It is detected by engine coolant temp. sensor
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim value represents short term
corrections to the air / fuel mixture computation. A val-
ue of 0 indicates no correction, a value greater than
0 means an enrichment correction, and a value less
than 0 implies an enleanment correction.
LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim Value represents long term correc-
tions to the air / fuel mixture computation. A value of 0
indicates no correction, a value greater than 0 means
an enrichment correction, and a value less than 0 im-
plies an enleanment correction.
MAP (INTAKE MANIFOLD ABSOLUTE
PRESSURE, kPa, inHg)
It is detected by manifold absolute pressure sensor and
used (among other things) to compute engine load.
ENGINE SPEED (rpm)
It is computed by reference pulses from crankshaft
position sensor.
VEHICLE SPEED (km / h, MPH)
It is computed based on pulse signals from vehicle
speed sensor.
IGNITION ADVANCE
(IGNITION TIMING ADVANCE FOR NO.1
CYLINDER, )
Ignition timing of NO.1 cylinder is commanded by
ECM (PCM). The actual ignition timing should be
checked by using the timing light.
INTAKE AIR TEMP. (C, F)
It is detected by intake air temp. sensor and used to
determine the amount of air passing into the intake
manifold as air density varies with temperature.
MAF (MASS AIR FLOW RATE, gm / s, lb / min)
It represents total mass of air entering intake manifold
which is computed based on signals from MAP sen-
sor, IAT sensor, TP sensor, etc.
THROTTLE POS
(ABSOLUTE THROTTLE POSITION, %)
When throttle position sensor is fully closed position,
throttle opening is indicated as 0% and 100% full open
position.
OXYGEN SENSOR B1 S1
(HEATED OXYGEN SENSOR-1, V)
It indicates output voltage of HO2S-1 installed on ex-
haust manifold (pre-catalyst).
OXYGEN SENSOR B1 S2
(HEATED OXYGEN SENSOR-2, V)
It indicates output voltage of HO2S-2 installed on ex-
haust pipe (post-catalyst). It is used to detect catalyst
deterioration.
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM (PCM) internal pa-
rameter which indicates the ECM (PCM) requested
idle. If the engine is not running, this number is not valid.
TP SENSOR VOLT (THROTTLE POSITION
SENSOR OUTPUT VOLTAGE, V)
The Throttle Position Sensor reading provides throttle
valve opening information in the form of voltage.
INJ PULSE WIDTH
(FUEL INJECTION PULSE WIDTH, msec.)
This parameter indicates time of the injector drive
(valve opening) pulse which is output from ECM
(PCM) (but injector drive time of NO.1 cylinder for
multiport fuel injection).
IAC FLOW DUTY (IDLE AIR (SPEED) CONTROL
DUTY, %)
This parameter indicates current flow time rate within
a certain set cycle of IAC valve (valve opening rate)
which controls the amount of bypass air (idle speed).
TOTAL FUEL TRIM (%)
The value of Total Fuel Trim is obtained by putting val-
ues of short Term Fuel Trim and Long Term Fuel Trim
together. This value indicates how much correction is
necessary to keep the air / fuel mixture stoichiomet-
rical.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage in-
putted from main relay to ECM (PCM).
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-33
1. ECM (PCM)
2. ECM (PCM) couplers
(Viewed from harness side)
INSPECTION OF ECM (PCM) AND ITS
CIRCUITS
ECM (PCM) and its circuits can be checked at ECM (PCM) wiring
couplers by measuring voltage and resistance.
CAUTION:
ECM (PCM) cannot be checked by itself. It is strictly prohib-
ited to connect voltmeter or ohmmeter to ECM (PCM) with
coupler disconnected from it.
Voltage Check
1) Remove ECM (PCM) (1) from body referring to Section 6E2.
2) Check voltage at each terminal of couplers (2) connected.
NOTE:
As each terminal voltage is affected by the battery voltage,
confirm that it is 11 V or more when ignition switch is ON.
1 2
1. ECM (PCM) coupler disconnected
2. Ohmmeter
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-37
Resistance Check
1) Disconnect ECM (PCM) couplers from ECM (PCM) with ignition
switch OFF.
CAUTION:
Never touch terminals of ECM (PCM) itself or connect
voltmeter or ohmmeter.
2) Check resistance between each terminal of couplers discon-
nected.
CAUTION:
Be sure to connect ohmmeter probe from wire harness
side of coupler.
Be sure to turn OFF ignition switch for this check.
Resistance in table below represents that when parts
temperature is 20C (68F).
TERMINALSCIRCUITSTANDARD RESISTANCE
C01-7 to C03-6HO2S-1 heater11.7 – 15.6 Ω
C02-4 to C03-6HO2S-2 heater11.7 – 15.6 Ω
C01-9 to C02-5 / 6No.1 injector12.0 – 13.0 Ω
C01-21 to C02-5 / 6No.2 injector12.0 – 13.0 Ω
C01-31 to C02-5 / 6No.3 injector12.0 – 13.0 Ω
C01-8 to C02-5 / 6No.4 injector12.0 – 13.0 Ω
C02-2 to C02-5 / 6EGR valve (stepper motor coil 4)20 – 24 Ω
C02-9 to C02-5 / 6EGR valve (stepper motor coil 3)20 – 24 Ω
C02-8 to C02-5 / 6EGR valve (stepper motor coil 2)20 – 24 Ω
C02-17 to C02-5 / 6EGR valve (stepper motor coil 1)20 – 24 Ω
C01-4 to C02-5 / 6EVAP canister purge valve30 – 34 Ω
C02-19 to C03-6Fuel pump relay70 – 110 Ω
C02-1 to Body groundA / C control moduleNo continuity
C02-18 to C02-5 / 6Radiator fan control relay70 – 110 Ω
C02-10 to C02-7Main relay70 – 110 Ω
C01-1 to Body groundGroundContinuity
C01-2 to Body groundGroundContinuity
C01-3 to Body groundGroundContinuity
Main
fuseIgnition
switch
Main
relay Malfunction indicator lamp in combination meter
Relay
box Fuse box
C01-1
C01-2
C01-3
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-39
TABLE A-1 MALFUNCTION INDICATOR LAMP CIRCUIT CHECK – LAMP DOES
NOT COME “ON” AT IGNITION SWITCH ON (BUT ENGINE AT STOP)
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, ECM (PCM) causes the main relay to turn ON (close the contact point).
Then, ECM (PCM) being supplied with the main power, turns ON the malfunction indicator lamp (MIL). When the
engine starts to run and no malfunction is detected in the system, MIL goes OFF but if a malfunction was or is de-
tected, MIL remains ON even when the engine is running.
INSPECTION
STEPACTIONYESNO
1MIL Power Supply Check
1) Turn ignition switch ON.
Do other indicator / warning lights in
combination meter comes ON?Go to Step 2.“IG” fuse blown, main
fuse blown, ignition switch
malfunction, “B/W” circuit
between “IG” fuse and
combination meter or poor
coupler connection at
combination meter.
2ECM (PCM) Power and Ground Circuit
Check Does engine start?Go to Step 3.Go to TABLE A-3 ECM (PCM)
POWER AND GROUND
CIRCUIT CHECK.
If engine is not cranked, go to
DIAGNOSIS in SECTION 6G.
3MIL Circuit Check
1) Turn ignition switch OFF and disconnect
connectors from ECM (PCM).
2) Check for proper connection to ECM
(PCM) at terminal C03-1.
3) If OK, then using service wire, ground
terminal C03-1 in connector
disconnected.
Does MIL turn on at ignition switch ON?Substitute a
known-good ECM
(PCM) and recheck.Bulb burned out or “V” wire
circuit open.
6-1-40 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
TABLE A-2 MALFUNCTION INDICATOR LAMP CIRCUIT CHECK – LAMP
REMAINS “ON” AFTER ENGINE STARTS
WIRING DIAGRAM / CIRCUIT DESCRIPTION – Refer to table A-1.
INSPECTION
STEPACTIONYESNO
1Diagnostic Trouble Code (DTC) check
1) Check DTC referring to DTC CHECK section.
Is there any DTC(s)?Go to Step 2 of ENGINE
DIAG. FLOW TABLE.Go to Step 2.
2DTC check
Start engine and recheck DTC while engine
running.
Is there any DTC(s)?Go to Step 3.
3MIL Circuit check
1) Turn OFF ignition switch.
2) Disconnect connectors from ECM (PCM).
Does MIL turn ON at ignition switch ON?“V” wire circuit shorted to
ground.Substitute a known-good
ECM (PCM) and
recheck.