6-1-22 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
ENGINE DIAGNOSIS TABLE
Perform troubleshooting referring to following table when ECM (PCM) has detected no DTC and no abnormality
has been found in visual inspection and engine basic inspection previously.
Condition
Possible CauseReferring Item
Hard Starting
(Engine cranks OK)Ignition system out of order
Faulty spark plug
Leaky high-tension cord
Loose connection or disconnection of high-
tension cords or lead wires
Faulty ignition coil
Fuel system out of order
Dirty or clogged fuel hose or pipe
Malfunctioning fuel pump
Air inhaling from intake manifold gasket or
throttle body gasket
Engine and emission control system out of
order
Faulty idle air control system
Faulty ECT sensor or MAP sensor
Faulty ECM (PCM)
Low compression
Poor spark plug tightening or faulty gasket
Compression leak from valve seat
Sticky valve stem
Weak or damaged valve springs
Compression leak at cylinder head gasket
Sticking or damaged piston ring
Worn piston, ring or cylinder
Others
Malfunctioning PCV valve
Spark plugs in Section 6F1
High-tension cords in Section 6F1
High-tension cords in Section 6F1
Ignition coil in Section 6F1
Diagnostic Flow Table B-3
Diagnostic Flow Table B-3
Diagnostic Flow Table B-4
ECT sensor or MAP sensor in
Section 6E2
Compression check in Section
6A1
Spark plugs in Section 6F1
Valves inspection in Section 6A1
Valves inspection in Section 6A1
Valve springs inspection in
Section 6A1
Cylinder head inspection in
Section 6A1
Cylinders, pistons and piston rings
inspection in Section 6A1
Cylinders, pistons and piston rings
inspection in Section 6A1
PCV system in Section 6E2
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-23
ConditionPossible Cause]Referring Item
Low oil pressureImproper oil viscosity
Malfunctioning oil pressure switch
Clogged oil strainer
Functional deterioration of oil pump
Worn oil pump relief valve
Excessive clearance in various sliding partsEngine oil and oil filter change in
Section 0B
Oil pressure switch inspection in
Section 8
Oil pan and oil pump strainer
cleaning in Section 6A1
Oil pump in Section 6A1
Oil pump in Section 6A1
Engine noise
Note: Before
checking mechanical
noise, make sure
that:
Specified spark
plug in used.
Specified fuel is
used.Valve noise
Improper valve lash
Worn valve stem and guide
Weak or broken valve spring
Warped or bent valve
Piston, ring and cylinder noise
Worn piston, ring and cylinder bore
Connecting rod noise
Worn rod bearing
Worn crank pin
Loose connecting rod nuts
Low oil pressure
Crankshaft noise
Low oil pressure
Worn bearing
Worn crankshaft journal
Loose bearing cap bolts
Excessive crankshaft thrust play
Valve lash in Section 6A1
Valves inspection in Section 6A1
Valve springs inspection in
Section 6A1
Valves inspection in Section 6A1
Pistons and cylinders inspection
in Section 6A1
Crank pin and connecting rod
bearing inspection in Section 6A1
Crank pin and connecting rod
bearing inspection in Section 6A1
Connecting rod installation in
Section 6A1
Previously outlined
Previously outlined
Crankshaft and bearing
inspection in Section 6A1
Crankshaft and bearing
inspection in Section 6A1
Crankshaft inspection in
Section 6A1
Crankshaft thrust play inspection
in Section 6A1
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).
6-1-34 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
CONNECTOR “C01”
TERMINAL
NO.CIRCUITNORMAL
VOLTAGECONDITION
1Ground——
2Ground——
3Ground——
4EVAP canister purge valve10 – 14 VIgnition switch ON
Indication
deflection
5Power steering switch
deflection
repeated
0 V and
Ignition switch ON
0 V and
10 – 14 V
6Idle air control valve0 – 13 VAt specified idle speed after engine warmed
up
7Heater of HO2S-110 – 14 VIgnition switch ON
8Fuel injector NO.410 – 14 VIgnition switch ON
9Fuel injector NO.110 – 14 VIgnition switch ON
10Sensor ground——
11Camshaft position sensor0 – 0.8 V
and 4 – 6 VIgnition switch ON
12Blank——
13Heater oxygen sensor-1Refer to DTC P0130 diag. flow table
14Engine coolant temp. sensor0.55 – 0.95 VIgnition switch ON
Engine coolant temp.: 80C (176F)
15Intake air temp. sensor2.0 – 2.7 VIgnition switch ON
Intake air temp.: 20C (68F)
16Blank——
17Electric load signal (+)
0 – 1 VIgnition switch ON
Small light and rear defogger OFF
17Electric load signal (+)
10 – 14 VIgnition switch ON
Small light and rear defogger ON
18Blank——
19Ignition coil #2——
20Ignition coil #1——
21Fuel injector NO.210 – 14 VIgnition switch ON
22Power source for sensor4.75 – 5.25 VIgnition switch ON
23Crankshaft position sensor (+)——
24Crankshaft position sensor (–)——
25Blank——
26Manifold absolute pressure
sensor3.3 – 4.0 VIgnition switch ON
Barometric pressure: 100 kPa (760 mmHg)
27Blank——
28Immobilizer indicator lamp0 – 2 VIgnition switch ON28Immobilizer indicator lamp10 – 14 VWhen engine running
29Blank——
30Blank——
31Fuel injector NO.310 – 14 VIgnition switch ON
6-1-36 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
CONNECTOR “C03”
TERMINAL
NO.CIRCUITNORMAL
VOLTAGECONDITION
1Malfunction indicator lamp0 – 1 VIgnition switch ON1Malfunction indicator lamp10 – 14 VWhen engine running
2
Vehicle speed sensor (M / T)
Indicator
deflection
repeated
0 V and
4 – 6 V
Ignition switch ON
Front left tire turned slowly with front right
tire locked
Output shaft speed sensor
(+) (A / T)0.4 – 0.8 VIgnition switch ON
3Blank——
4Shift solenoidA(A / T)0 VIgnition switch ON, Select lever at P-range4Shift solenoid – A (A / T)10 – 14 VIgnition switch ON, Select lever at D-range
5Throttleposition sensor
0.2 – 1.0 VIgnition switch ON
Throttle valve at idle position
5Throttle position sensor
2.8 – 4.8 VIgnition switch ON
Throttle valve at full open position
6Ignition switch10 – 14 VIgnition switch ON
7Data link connector—Ignition switch ON
8Output shaft speed sensor
(–) (A / T)0.4 – 0.8 VIgnition switch ON
9Blank——
10Sensor ground——
11Shift solenoidB(A / T)0 VIgnition switch ON, Select lever at P-range11Shift solenoid – B (A / T)10 – 14 VIgnition switch ON, Select lever at D-range
12Blank——
13Blank——
14Blank——
15Blank——
16Tachometer (if equipped)0 – 1 VIgnition switch ON
17Engine start switch6 – 12 VWhile engine cranking17g
(Engine start signal)0 – 1 VOther than above
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.
Main
fuseIgnition
switch
Main
relay Malfunction indicator lamp in combination meter
Relay
box
Fuse box
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-41
TABLE A-3 ECM (PCM) POWER AND GROUND CIRCUIT CHECK – MIL
DOESN’T LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN’T
START THOUGH IT IS CRANKED UP
CIRCUIT DESCRIPTION
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is sup-
plied to ECM (PCM).
INSPECTION
STEPACTIONYESNO
1Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch ON?Go to Step 5.Go to Step 2.
2Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1) at terminal
3 and 4.
3) Check resistance between each two terminals. See Fig. 1
and 2.
Between terminals 1 and 2: Infinity
Between terminals 3 and 4: 100 – 150 Ω
4) Check that there is continuity between terminals 1 and 2
when battery is connected to terminals 3 and 4. See Fig. 3.
Is main relay in good condition?Go to Step 3.Replace main
relay.
3Fuse Check
Is main “FI” fuse in good condition?Go to Step 4.Check for short in
circuits connected
to this fuse.
4ECM (PCM) Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from ECM
(PCM) and install main relay.
2) Check for proper connection to ECM (PCM) at terminals
C03-6, C02-10, C02-5 and C02-6.
3) If OK, then measure voltage between terminal C03-6 and
ground, C02-10 and ground with ignition switch ON.
Is each voltage 10 – 14 V?Go to Step 5.“B/W”, “W/R” or
“Gr” circuit open.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-69
Ignition coil assembly
for No.1 & No.4 spark plugs
Ignition coil assembly
for No.2 & No.3 spark plugs
Ignition switch
Main relay
Main
fuseRelay box
To ignition switch
CKP sensorCMP sensorNo.1 injector
No.2 injector
No.3 injector
No.4 injector Fuse box
DTC P0300 RANDOM MISFIRE DETECTED (Misfire detected at 2 or more
cylinders)
DTC P0301 CYLINDER 1 MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
DTC P0304 CYLINDER 4 MISFIRE DETECTED
CIRCUIT DESCRIPTION
ECM (PCM) monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylin-
der No. via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from
how many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM (PCM) detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to
the three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times under
the same driving conditions.
Also, when ECM (PCM) detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three
way catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2
driving cycle detection logic.