Page 225 of 557

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.
Page 226 of 557

Below
specified value
6-1-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
1. CKP sensor signal
2. No.1 fuel injector signal
3. No.3 fuel injector signal
4. Fuel injection time
Display of fuel injection signal using oscilloscope
Waveforms at specified idle speed5ms/Div
DTC DETECTING CONDITIONPOSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
EGR system malfunction
DTC CONFIRMATION PROCEDURE
NOTE:
Among different types of random misfire, if misfire occurs at cylinders 1 and 4 or cylinders 3 and 2 simulta-
neously, it may not possible to reconfirm DTC by using the following DTC confirmation procedure. When
diagnosing the trouble of DTC P0300 (Random misfire detected) of the engine which is apparently misfir-
ing, even if DTC P0300 cannot be reconfirmed by using the following DTC confirmation procedure, pro-
ceed to the following Diag. Flow Table.
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Intake air temp.: between –10C and 80C (14F and 176F)
–Engine coolant temp.: –10C, 14F or higher
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.
Reference
Page 227 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-71
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE“.
2Is there DTC other than Fuel system (DTC P0171 / P0172)
and misfire (DTC P0300-P0304)?Go to applicable
DTC Diag.
Flow Table.Go to Step 3.
3Check Ignition System.
1) Remove spark plugs and check them for;
Air gap: 1.0 – 1.1 mm (0.040 – 0.043 in.) See Fig. 1.
Carbon deposits
Insulator damage
Plug type
If abnormality is found, adjust, clean or replace.
2) Disconnect all injector connectors. See Fig. 2.
3) Connect spark plugs to high tension cords and then ground
spark plugs.
4) Crank engine and check that each spark plug sparks.
Are above check results satisfactory?Go to Step 4.Check ignition
system parts
(Refer to Section
6F1).
4Check Fuel Pressure (Refer to Section 6E2 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge. See Fig. 3.
3) Check fuel pressure.
With fuel pump operating
and engine at stop : 270 – 310 kPa, 2.7 – 3.1 kg / cm
2,
38.4 – 44.0 psi.
At specified idle speed : 200 – 240 kPa, 2.0 – 2.4 kg / cm
2,
28.4 – 34.1 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 fuel
pressure check.
5Check Fuel Injectors and Circuit.
1) Using sound scope (1) or such, check operating sound of
each injector (2) when engine is running. Cycle of
operating sound should very according to engine speed.
See Fig 4.
If no sound or an unusual sound is heard, check injector
circuit (wire or coupler) or injector.
2) Turn ignition switch OFF and disconnect a fuel injector
connector.
3) Check for proper connection to fuel injector at each
terminal. See Fig. 5.
4) If OK, then check injector resistance.
Injector Resistance: 12 – 13 ohm at 20C (68F)
5) Carry out steps 1) and 3) on each injector.
6) Check each injector for injected fuel volume referring to
Section 6E2. See Fig. 6.
Injected Fuel Volume: 38 – 48 cc / 15 sec (1.28 / 1.34 –
1.62 / 1.69 US / Imp. oz / 15 sec)
7) Check each injector for fuel leakage after injector closed.
Fuel Leakage: Less than 1 drop / min.
Is check result in step 1) and 3) to 7) satisfactory?Go to Step 6.Check injector
circuit or replace
fuel injector(s).
Page 228 of 557

6-1-72 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
Disconnect connectors when checking plugs
for spark1. Fuel delivery pipe
2. Fuel feed hose
3. FUel pressure
gauge & 3 way joint
STEPACTIONYESNO
6Check PCV valve for clogging (See Section 6E2).
Is it in good condition?Go to Step 7.Replace PCV valve.
7Check EVAP Canister Purge Valve for Closing.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there, when engine is
cool and running at idle. See Fig. 7.
Is vacuum felt?Check EVAP
control system
(See Section 6E2).Go to Step 8.
8Check intake manifold pressure sensor for performance
(See DTC P0105 Diag. Flow Table).
Is it in good condition?Go to Step 9.Repair or replace.
9Check engine coolant temp. sensor for performance
(See Section 6E2).
Is it in good condition?Go to Step 10.Replace engine
coolant temp.
sensor.
10Check parts or system which can cause engine rough
idle or poor performance.
–Engine compression (See Section 6A1).
–Valve lash (See Section 6A1).
–Valve timing (Timing belt installation. See Section 6A1).
Are they in good condition?Check wire harness
and connection of
ECM (PCM) ground,
ignition system and
fuel injector for
intermittent open
and short.Repair or replace.
Fig. 1 for Step 3 Fig. 2 for Step 3 Fig. 3 for Step 4
Fig. 4 for Step 5 Fig. 5 for Step 4 Fig. 6 for Step 5
Fig. 7 for Step 7
Page 229 of 557
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-73
Crankshaft
timing belt
pulleyCKP
sensor
Oscilloscope Waveforms
Waveforms at engine cranking (260 r/min) Waveforms at specified idle speed16 waives
for 10 signals13 waives for
10 signals
30 signal 30 signal 0.5 V / Div.
10 ms / Div.0.5 V / Div.
5 ms / Div.
DTC P0335 CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
NO CKP sensor signal for 2 seconds at engine
cranking.CKP sensor circuit open or short.
Crankshaft timing belt pulley teeth damaged.
CKP sensor malfunction, foreign material being
attached or improper installation.
ECM (PCM) malfunction.
Reference
Connect oscilloscope between terminals C01-23 (+) and C01-24 (–) of ECM (PCM) connector connected to ECM
(PCM) and check CKP sensor signal.
DTC CONFIRMATION PROCEDURE
1) Clear DTC and crank engine for 2 sec.
2) Select “DTC” mode on scan tool and check DTC.
Page 230 of 557

6-1-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
INSPECTION
NOTE:
If starter circuit is open (i.e., start signal circuit is OK but starter fails to run), this DTC is stored in memory
at starter switch ON, even though CKP sensor is in good condition.
When starter motor fails to run and this DTC appears, check starter circuit first.
STEP
ACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Is there DTC P1500 (Engine starter signal circuit)?Go to DTC P1500
Diag. Flow Table.Go to Step 3.
3Check CKP Sensor for Resistance.
1) Disconnect CKP sensor connector with ignition
switch OFF.
2) Then check for proper connection to CKP sensor
at “W” and “B” wire terminals.
3) If OK, measure sensor resistance between
terminals. See Fig. 1.
CKP sensor resistance: 360 – 460 Ω at 20C,
68F
4) Measure resistance between each terminal and
ground.
Insulation resistance: 1 MΩ or more.
Were measured resistance valves in step 3) and 4)
as specified?Go to Step 4.Replace CKP sensor.
4Check visually CKP sensor and pulley for the
following. See Fig. 2.
Damage
No foreign material attached.
Correct installation.
Are they in good condition?“W” or “B” wire open or
shorted to ground, or
poor connection at
C01-23 or C01-24.
If wire and connection
are OK, intermittent
trouble or faulty ECM
(PCM).
Recheck for
intermittent referring
to “Intermittent and
Poor Connection” in
Section 0A.Clean, repair or
replace.
Fig. 1 for Step 3 Fig. 2 for Step 4
Page 231 of 557
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-75
To ignition
switch
Signal rotor
on CamshaftCamshaft
position
sensor
Waveforms at specified idle speed
Oscilloscope Waveforms
2 V / Div.
Crank
angle20 ms / Div.
180
720
DTC P0340 CAMSHAFT POSITION (CMP) SENSOR CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
No CMP sensor signal during engine running
(CKP sensor signal is inputted).CMP sensor circuit open or short.
Signal rotor teeth damaged.
CMP sensor malfunction, foreign material being
attached or improper installation.
ECM (PCM) malfunction.
Reference
Connect oscilloscope between terminals C01-11 of ECM (PCM) connector connected to ECM (PCM) and body
ground and check CKP sensor signal.
DTC CONFIRMATION PROCEDURE
1) Clear DTC.
2) Start engine and keep it at idle for 1 min.
3) Select “DTC” mode on scan tool and check DTC.
Page 232 of 557

6-1-76 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Check CMP Sensor and connector for proper
installation.
Is CMP sensor installed properly and connector
connected securely?Go to Step 3.Correct.
3Check Wire Harness and Connection.
1) Disconnect connector from CMP sensor.
2) Check for proper connection to CMP sensor at
each terminal.
3) If OK, turn ignition switch ON and check for voltage
at each terminal of sensor connection
disconnected. See Fig. 1.
Terminal “B+”: 10 – 14 V
Terminal “Vout”: 4 – 5 V
Terminal “GND”: – 0 V
Is check result satisfactory?Go to Step 5.Go to Step 4.
4Was terminal “Vout” voltage out of specification in
Step 3 check?“B/W” wire open,
short or poor
connection. If wire and
connection are OK,
substitute a known-
good ECM (PCM) and
recheck.“B/W” or “B” wire
open, short or poor
connection.
5Check Ground Circuit for Open.
1) Turn ignition switch OFF.
2) Check for continuity between “GND” terminal of
CMP sensor connector and engine ground.
Is continuity indicated?Go to Step 6.“B” wire open or poor
ground connection.
6Check CMP Sensor for Operation.
1) Remove CMP sensor from sensor case.
2) Remove metal particles on end face of CMP
sensor, if any.
3) Connect each connector to ECM (PCM) and CMP
sensor.
4) Turn ignition switch ON.
5) Check for voltage at terminal C01-11 of connector
connected to ECM (PCM) by passing magnetic
substance (iron) while keeping approximately
1 mm (0.03 in.) gap with respect to end face of
CMP sensor. See Fig. 2 and 3.
Does voltage vary from low (0 – 1 V) to high (4 – 5 V)
or from high to low?Go to Step 7.Replace CMP sensor.