ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-27
ConditionPossible CauseReferring Item
Improper engine
idling or engine
fails to idleIgnition system out of order
Faulty spark plug
Leaky or disconnected high-tension cord
Faulty ignition coil with ignitor
Fuel system out of order
Fuel pressure out of specification
Leaky manifold, throttle body, or cylinder head
gasket
Engine and emission control system out of
order
Malfunctioning EGR valve
Faulty idle air control system
Faulty evaporative emission control system
Faulty EGR system
Faulty fuel injector(s)
Poor performance of ECT sensor, TP sensor or
MAP sensor
Faulty ECM (PCM)
Engine overheating
Low compression
Others
Loose connection or disconnection of vacuum
hoses
Malfunctioning PCV valve
Spark plugs in Section 6F
High-tension cords in Section 6F
Ignition coil in Section 6F
Diagnostic Flow Table B-3
EGR system in Section 6E2
Diagnostic Flow Table B-4
EVAP control system in Section
6E2
EGR system in Section 6E2
Diagnostic Flow Table B-1
ECT sensor, TP sensor or MAP
sensor in Section 6E2
Refer to “Overheating” section
Previously outlined
PCV system in Section 6E2
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) 6-1-31
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).
6-1-32 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
CANIST PURGE DUTY (EVAP CANISTER
PURGE FLOW DUTY, %)
This parameter indicates valve ON (valve open) time
rate within a certain set cycle of EVAP purge solenoid
valve which controls the amount of EVAP purge.
0% means that the purge valve is completely closed
while 100% is a fully open valve.
CLOSED THROTTLE POSITION (ON / OFF)
This parameter will read ON when throttle valve is ful-
ly closed, or OFF when the throttle is not fully closed.
FUEL CUT (ON / OFF)
ON : Fuel being cut (output signal to injector is
stopped)
OFF : Fuel not being cut
RADIATOR FAN
(RADIATOR FAN CONTROL RELAY, ON / OFF)
ON : Command for radiator fan control relay opera-
tion being output.
OFF : Command for relay operation not being out-
put.
ELECTRIC LOAD (ON / OFF)
ON : Headlight, small light, heater fan or rear win-
dow defogger ON signal inputted.
OFF : Above electric loads all turned OFF.
A / C SWITCH (ON / OFF)
ON : Command for A / C operation being output
from ECM (PCM) to A / C amplifier.
OFF : Command for A / C operation not being output.
FUEL TANK LEVEL (%)
This parameter indicates approximate fuel level in the
fuel tank. As the detectable range of the fuel level sen-
sor is set as 0 to 100%, however, with some models
whose fuel tank capacity is smaller, the indicated fuel
level may be only 70% even when the fuel tank is full.
PNP SIGNAL (PARK / NEUTRAL POSITION
SIGNAL, P / N RANGE or D RANGE)
It is detected by signal from TCM.
D range : A / T is in “R”, “D”, “2” or “L” range.
P / N range : A / T is in “P” or “N” range or the above
signal is not inputted from TCM.
EGR VALVE (%)
This parameter indicates opening rate of EGR valve
which controls the amount of EGR flow.
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
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
INFORMATION SENSORS
-1. MAP sensor
-2. TP sensor
-3. IAT sensor
-4. ECT sensor
-5. Heated oxygen sensor-1
5-1. Heated oxygen sensor-2
-6. VSS (A / T)
-7. Transmission range switch (A / T)
-8. Battery
-9. CMP sensor
-10. CKP sensor
-11. Fuel level sensor (gauge) (in fuel tank)
-12. PSP switch
-13. A / C control module (if equipped)
-14. VSS (speedometer) (M / T)OTHERS
A: ECM (PCM)
B: Main relay
C: EVAP canister
D: Data link connector CONTROL DEVICES
a: Fuel injector
b: EVAP canister purge valve
c: Fuel pump relay
d: EGR valve (step motor)
e: Malfunction indicator lamp
f: Ignition coil assembly
g: Radiator fan control relay
h: IAC valve
6-1-38 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
COMPONENT LOCATION
ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13) 6-1-65
Ignition
switch
Main
fuseMain relay
To ignition
switchTo other sensor Relay boxNo.1 injector
No.2 injector
No.3 injector
No.4 injector Fuse box
Signal to decrease amount of fuel injection
Signal to increase amount of fuel injection
High voltage
Low voltage
A / F mixture
becomes
richerOxygen
concentration
decreases
A / F mixture Oxygen
Fuel injectorSensed
information
A / F mixture
Exhaust gas
becomes
leanerconcentration
increases
DTC P0171 FUEL SYSTEM TOO LEAN
DTC P0172 FUEL SYSTEM TOO RICH
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
When following condition occurs while engine running under
closed loop condition.
–Air / fuel ratio too lean
Total fuel trim (short and long terms added) is
more than 30%
or
–Air / fuel ratio too rich
(Total fuel trim is less than –30%)
2 driving cycle detection logic, continuous monitoring.Vacuum leaks (air drawn in).
Exhaust gas leakage.
Heated oxygen sensor-1 circuit
malfunction.
Fuel pressure out of specification.
Fuel injector malfunction (clogged or
leakage).
MAP sensor poor performance.
ECT sensor poor performance.
IAT sensor poor performance.
TP sensor poor performance.
EVAP control system malfunction.
PCV valve malfunction.