IAT SUZUKI SWIFT 2008 2.G Service Owner's Manual

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-21
Component Location
Electronic Control System Components LocationS7RS0B1103001
NOTE
The figure shows left-hand steering vehicle. For right-hand steering vehicle, parts with (*) are installed
at the opposite side.

I*
E*
G*
D
K H*
J
C*
7
A
F
c
L
i m
f
B*
e
g
k
l
13
3*
4
j
10 12 h
58
a
9
b
1
5-1
d
2
11
6
14*
I7RS0B110011-02
Information sensors Control devices Others
1. MAF and IAT sensor a: Fuel injectorA: ECM
2. TP sensor b: EVAP canister purge valve B: Combination meter
3. Brake light switch c: Fuel pump relayC: EVAP canister
4. ECT sensor d: EGR valveD: A/C evaporator outlet air temp. sensor (manual A/C model)
5. HO2S-1 e: MILE: Data link connector
5-1. HO2S-2 f: Radiator cooling fan relay No.3F: A/C compressor relay
6. Wheel speed sensor (VSS) g: Immobilizer indicator lightG: TCM (A/T model)
7. Battery h: Ignition coil assembly (with ignitor) H: BCM (included in junction block assembly)
8. CMP sensor i: Main relayI: Immobilizer coil antenna
9. MAP sensor j: Oil control valveJ: EPS control module
10. CKP sensor k: Radiator cooling fan relay No.2K: A/C refrigerant pressure sensor
11. Fuel level sensor l: Radiator cooling fan relay No.1L: Diagnosis connector (Hong Kong model)
12. Knock sensor m: Starting motor control relay
13. Electric load current sensor
14. APP sensor

Downloaded from www.Manualslib.com manuals search engine 1A-28 Engine General Information and Diagnosis:
) *P0031 HO2S heater control circuit low
(Sensor-1) Heater voltage is less than specification while heater ON. 2 driving
cycles
) *P0032 HO2S heater control circuit
high (Sensor-1) Heater voltage is more than
specification while heater
ON. 2 driving
cycles
) *P0037 HO2S heater control circuit low
(Sensor-2) Heater voltage is less than specification while heater ON. 2 driving
cycles
) *P0038 HO2S heater control circuit
high (Sensor-2) Heater voltage is more than
specification while heater
ON. 2 driving
cycles
)
U *P0101 Mass or volume air flow circuit
range/performance MAF sensor volume is more
than specification or less
than specification. 2 driving
cycles
) *P0102 Mass or volume air flow circuit
low input Output voltage of MAF sensor is less than specification. 1 driving
cycle
) *P0103 Mass or volume air flow circuit
high input Output voltage of MAF sensor is more than specification. 1 driving
cycle
)
U *P0106 Manifold absolute pressure/
barometric pressure circuit
range/performance Difference between Max. manifold absolute pressure
value and Min. manifold pressure value is less than
specification or difference between barometric pressure
value and manifold pressure value is less than
specification
2 driving
cycles
) *P0107 Manifold absolute pressure/
barometric pressure circuit low
input Output voltage of MAP sensor
is less than specification.1 driving
cycle
) *P0108 Manifold absolute pressure/
barometric pressure circuit high
input Output voltage of MAP sensor is more than specification.
1 driving
cycle
)
U *P0111 Intake air temperature sensor 1
circuit range/performance Variation of intake air temperature from engine start is
less than specification. 2 driving
cycles
) *P0112 Intake air temperature sensor 1
circuit low Circuit voltage of IAT sensor is less than specification. 1 driving
cycle
) *P0113 Intake air temperature sensor 1
circuit hig

h Circuit voltage of IAT sensor
is more than specification. 1 driving
cycle
)
U *P0116 Engine coolant temperature
circuit range/performance Engine coolant temperature is less than specified
temperature for specified time from engine start. 2 driving
cycles
) *P0117 Engine coolant temperature
circuit low Circuit voltage of ECT sensor
is less than specification. 1 driving
cycle
) *P0118 Engine coolant temperature
circuit high Circuit voltage of ECT sensor
is more than specification. 1 driving
cycle
) *P0122 Throttle/pedal position sensor/
switch “A” circuit low Output voltage of TP sensor (main) is lower than
specification. 1 driving
cycle
) *P0123 Throttle/pedal position sensor/
switch “A” circuit high Output voltage of TP sensor (main) is higher than
specification. 1 driving
cycle
)
U *P0131 O2 sensor (HO2S) circuit low
voltage (Sensor-1)
Max. output voltage of HO2S-1
is less than specification.2 driving
cycles
)
U *P0132 O2 sensor (HO2S) circuit high
voltage (Sensor-1)
Min. output voltage of HO2S-1
is more than specification. 2 driving
cycles
)
U *P0133 O2 sensor (HO2S) circuit slow
response (Sensor-1) Response time of HO2S-1 output voltage between rich
and lean is longer than specification. 2 driving
cycles
) *P0134 O2 sensor (HO2S) circuit no
activity detected (Sensor-1) Output voltage of HO2S-1 is
more than specification or
less than specification. (or HO2S-1 circuit open or short) 2 driving
cycles
)
U *P0137 O2 sensor (HO2S) circuit low
voltage (Sensor-2) Output voltage of HO2S-2 is
less than specification while
engine is idling after driving with high engine load and
Max. output voltage of HO2S-2 minus Min. output voltage
of HO2S-2 is less than specification. 2 driving
cycles
)
U *P013

8 O2 sensor (HO2S) circuit high
voltage (Sensor-2) Output voltage of HO2S-2 is
more than specification while
engine is idling after driving with high engine load and
Max. output voltage of HO2S-2 minus Min. output voltage
of HO2S-2 is less than specification. 2 driving
cycles
DTC No. Detecting item
Detecting condition
(DTC will set when detecting:) MIL

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-29
) *P0140 O2 sensor (HO2S) circuit no
activity detected (Sensor-2) Output voltage of HO2S-2 is more than specification after
warming up engine. 2 driving
cycles
)
{ *P0171 System too lean Total fuel trim is larger than
specification for specified time
or longer. (Fuel trim towa rd rich side is large.) 2 driving
cycles
)
{ *P0172 System too rich Total fuel trim is smaller th
an specification for specified
time or longer. (Fue l trim toward lean side is large.) 2 driving
cycles
) *P0222 Throttle/pedal position sensor
(sub)/switch “B” circuit low Output voltage of TP sensor (sub) is lower than
specification 1 driving
cycle
) *P0223 Throttle/pedal position sensor
(sub)/switch “B” circuit high Output voltage of TP sensor (sub) is higher than
specification 1 driving
cycle
)
U *P0300 Random/multiple cylinder
misfire detected Misfire of such level as to cause damage to three way
catalyst. *2 driving
cycles
)
U *P0301 /
U *P0302 /
U *P0303 /
U *P0304 Cylinder 1 misfire detected
Cylinder 2 misfire detected
Cylinder 3 misfire detected
Cylinder 4 misfire detected
Misfire of such level as to deteriorate emission but not to
cause damage to three way catalyst.
*2 driving
cycles
) *P0327 Knock sensor 1 circuit low Output voltage of knock sensor is less than specification.1 driving
cycle
) *P0328 Knock sensor 1 circuit high Output volta ge of knock sensor is more than specification.1 driving
cycle
) *P0335 Crankshaft position sensor “A”
circuit No signal of CKP sensor for sp
ecified time even if starting
motor signal is input. 1 driving
cycle
) *P0340 Camshaft position sensor “A”
circuit CMP sensor pulse is out of specification. 1 driving
cycle
) † P0350 Ignition c
oil primary /
secondary circuit Ignition signal is not inputted to monitor circuit 5 times or
more continuously. 1 driving
cycle
)
{ *P0401 Exhaust gas recirculation flow
insufficient detected Difference in intake manifold absolute pressure between
opened EGR valve and closed EGR valve is less than
specification. 2 driving
cycles
)
{ *P0402 Exhaust gas recirculation flow
excessive detected Difference in intake manifold absolute pressure between
opened EGR valve and closed EGR valve is more than
specification. 2 driving
cycles
) *P0403 Exhaust gas recirculation
control circuit Output voltage is different from output command with
more than one pole out of 4 poles. 1 driving
cycle
)
U *P0420 Catalyst system efficiency
below threshold
Output waveforms of HO2S-1 and HO2S-2 are similar. 2 driving
cycles
) *P0443 Evaporative emission system
purge control valve circuit Monitor signal of EVAP canister purge valve is different
from command signal. (circuit open or shorted to ground) 2 driving
cycles
) *P0480 Fan 1 (Radiator cooling fan)
control circuit Monitor signal of radiator cooling fan relay is different from
command signal. 1 driving
cycle
) *P0500 Vehicle speed sensor “A” No VSS signal during fuel cut fo
r specified time or longer,
or VSS signal is not input even if vehicle is driving with
more than specified engine speed and D-range (for A/T
model). 2 driving
cycles
) P0532 A/C refrigerant pressure sensor
“A” circuit low Output voltage of A/C refrigerant pressure sensor is less
than specification.
—
) P0533 A/C refrigerant pressure sensor
“A” circuit high Output voltage of A/C refrigerant pressure sensor is more
than specification.
—
) *P0601 Internal control module
memory check sum error Data write error or check sum error. 1 driving
cycle
) P0602 Control module programming
error Data programming error.
—
) *P0607 Control module performance Data programming error. 1 driving
cycle
)
U *P061

6Starter relay circuit low Starter signal is low voltage even though engine is started
with vehicle at stop. 2 driving
cycles
DTC No. Detecting item
Detecting condition
(DTC will set when detecting:) MIL

Downloaded from www.Manualslib.com manuals search engine 1A-32 Engine General Information and Diagnosis:
) P0117 Engine coolant temperature circuit low • EC M controls actuators assuming that engine
coolant temperature is 80 °C (176 °F).
• ECM operates radiator cooling fan.
)
P0118 Engine coolant temperature circuit high
) P0122 Throttle/pedal position sensor/switch/“A” (main)
circuit low • ECM turns off throttle actuator control relay and
throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
• ECM stops air/fuel ratio control.
)
P0123 Throttle/pedal position sensor/switch/“A” (main)
circuit high
) P0222 Throttle/pedal position sensor/switch/“B” (sub)
circuit low
) P0223 Throttle/pedal position sensor/switch/“B” (sub)
circuit high
) P0131 O2 sensor (HO2S) circuit low voltage (Sensor-1)
ECM stops air/fuel ratio control.
)
P0132 O2 sensor (HO2S) circuit high voltage (Sensor-1)
) P0134 O2 sensor (HO2S) circuit no activity detected
(Sensor-1)
) P0335 Crankshaft position sensor “A” circuit • Ignition timing is fixed.
• ECM changes injection control system from
sequential injection to simultaneous one.
) P0340 Camshaft position sensor “A” circuit ECM changes injection
control system from
sequential injection to simultaneous one.
) P0500 Vehicle speed sensor “A” • ECM controls actuators assuming that vehicle
speed is 0 km/h (0 mile/h).
• ECM stops IAC feedback control.
) P2101 Throttle actuator control motor circuit range /
performance • ECM turns off throttle actuator control relay and
throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
• ECM stops air/fuel ratio control.
)
P2102 Throttle actuator control motor circuit low
) P2103 Throttle actuator control motor circuit high ECM controls fuel cut at specified engine speed.
) P2111 Throttle actuator control system – stuck open • EC M turns off throttle actuator control relay and
throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
• ECM stops air/fuel ratio control.
)
P2112 Throttle actuator control system – stuck closed
) P2119 Throttle actuator control throttle body range /
performance • ECM turns off throttle actuator control relay and
throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
DTC No.
Detected item Fail-safe operation

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-33
Scan Tool DataS7RS0B1104007
As the data values are standard values estimated on the basis of values obtained from the normally operating vehicles
by using a scan tool, use them as re ference 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 that can be checked by the scan tool are those detected by ECM and output from ECM 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
• There are two types of OBD system depending on the vehicle specification.
For details, refer to “Precaution on On-Board Diagnostic (OBD) System”.
• With the generic scan tool, only star (*) marked data in the following table 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 position and A/T gear to the “Park” position and pull the parking brake fully. Also, if nothing
or “no load” is indicated, turn O FF A/C (if equipped with A/C), all electric loads, P/S and all the other
necessary switches.

) P2122 Throttle/pedal position sensor/switch/“D” (main)
circuit low input
• ECM turns off throttle actuator control relay and throttle valve is fixed at the specified opening from
its completely closed position (default opening).
For details, refer to “Description of Electric
Throttle Body System”.
• ECM controls fuel cut at specified engine speed.
• ECM stops air/fuel ratio control.
)
P2123 Throttle/pedal position sensor/switch/“D” (main)
circuit high input
) P2127 Throttle/pedal position sensor/switch/“E” (sub)
circuit low input
) P2128 Throttle/pedal position sensor/switch/“E” (sub)
circuit high input
) P2135 Throttle/pedal position sensor/switch/“A”/“B”
(main) / (sub) voltage correction
) P2138 Throttle pedal position sensor/switch “D”/“E”
(main) / (sub) voltage correlation
) P2227 Barometric pressure sensor performance problem ECM controls actuators assuming that barometric
pressure is 101.33 kPa (762 mmHg).
DTC No. Detected item Fail-safe operation
Scan tool data
Vehicle condition Normal condition /
reference values
* ) COOLANT TEMP At specified idle speed after warming up 80 – 100 °C, 176 – 212 °F
* ) INTAKE AIR TEMP. At specifie d idle speed after warming up –5
°C (23 °F) + environmental
temp. to 40 °C (104 °F) +
environmental temp.
* ) ENGINE SPEED It idling with no load after warming upDesired idle speed ± 50 rpm
) INJ PULSE WIDTH At specified idle speed with no load after warming up
2.0 – 4.0 msec.
At 2500 r/min. with no load after warming up 2.0 – 3.6 msec.
) DESIRED IDLE It idling with radiator cooling fan stopped and all electrical
parts turned OFF after warming up, M/T at neutral 700 rpm
* ) SHORT FT B1 At specified idle speed after warming up –20 – +20%
* ) LONG FT B1 At specified idle speed after warming up –20 – +20%
) TOTAL FUEL TRIM
B1 At specified idle speed after warming up
–35 – +35%
* ) MAF At specified idle speed wit
h no load after warming up 1.0 – 4.0 g/s 0.14 – 0.52 lb/
min.
At 2500 r/min. with no load after warming up 4.0 – 12.0 g/s 0.53 – 1.58 lb/
min.
* ) CALC LOAD At specified idle speed with no load after warming up
18 – 28%
At 2500 r/min. with no load after warming up 13 – 23%
* )
THROTTLE
POSITION Ignition switch ON /
warmed up engine
stoppedAccelerator pedal released
0 – 5%
Accelerator pedal depressed
fully 90 – 100%

Downloaded from www.Manualslib.com manuals search engine 1A-34 Engine General Information and Diagnosis:
*) O2S B1 S1 At specified idle speed after warming up 0.1 – 0.95 V
) O2S B1 S1 ACT At specified id le speed after warming up ACTIVE
* ) O2S B1 S2 At 2000 r/min. for 3 min. or longer after warming up. 0.1 – 0.95 V
) O2S B1 S2 ACT At specified id le speed after warming up ACTIVE
* ) FUEL SYSTEM B1 At specif ied idle speed after warming up CLSD (closed loop)
* ) MAP At specified idle speed with no load after warming up 24 – 38 kPa, 7.1 – 11.2 in.Hg
) BAROMETRIC
PRES —Barometric pressure is
displayed
) STEP EGR FLOW
DUTY At specified idle speed after warming up 0%
) FUEL CUT Engine at fuel cut condition ON
Engine at other than fuel cut condition OFF
) A/C PRESSURE Engine running A/C ON (A/C is operating) at
ambient temperature: 30
°C (86
° F) and humidity: 50% 1350 – 1650 kPa For more
details, refer to pressure of
high pressure gage under “A/C System Performance
Inspection in Section 7B” or “A/C Refrigerant Pressure Sensor and Its Circuit
Inspection in Section 7B”.
A/C OFF (A/C is not operating)
at ambient temperature: 30 ° C
(86 °F) and engine coolant
temperature: 90 – 100 °C (194 –
212 °F) 600 – 1000 kPa After longer
than 10 min from A/C switch turned off
) CLOSED
THROTTLE POS Throttle valve at idle position ON
Throttle valve opens larger than idle position OFF
) CANIST PRG DUTY At specified idle speed after warming up 0%
* ) IGNITION ADVANCE At specified idle s peed with no load after warming up 3 – 13 ° BTDC
) BATTERY VOLTAGE Ignition switch ON / engine at stop 10 – 14 V
) FUEL PUMP Within 2 seconds after ignition switch ON or engine
running
ON
Engine at stop with ignition switch ON OFF
) ELECTRIC LOAD Ignition switch ON / Headligh
t, small light, all turned OFF OFF
Ignition switch ON / Headli ght, small light, turned ON ON
) BRAKE SWITCH Igni tion switch ONBrake pedal is released OFF
Brake pedal is depressed ON
) RADIATOR FAN Ignition switch ON Engin
e coolant temp.: Lower
than 95 °C (203 °F) OFF
Engine coolant temp.: 97.5 °C
(208 °F) or higher ON
) BLOWER FAN Ignition switch ON Blower fan switch: 3rd speed
position or more
ON
Blower fan switch: under 2nd
speed position OFF
) A/C SWITCH Engine running after warming up, A/C not operating
OFF
Engine running after warming up, A/C operating ON
) A/C COMP RELAY Engine running A/C switch and blower motor
switch turned ON
ON
A/C switch and blower motor
switch turned OFF OFF
* ) VEHICLE SPEED At stop 0 km/h (0 mph)
) VVT GAP At specified idle speed after warming up 0 – 3°
) TP SENSOR 1 VOLT Ignition switch ON after
warmed up engine Accelerator pedal released
0.6 – 1.0 V
Accelerator pedal depressed
fully 3.37 – 4.55 V
Scan tool data
Vehicle condition Normal condition /
reference values

Downloaded from www.Manualslib.com manuals search engine 1A-36 Engine General Information and Diagnosis:
O2S B1 S1 ACT (HEATED OXYGEN SENSOR-1,
ACTIVE / INACTIVE)
This parameter indicates activation condition of HO2S-1.
ACTIVE: Activating
INACTIVE: warming up or at stop
O2S SENSOR B1 S2 (HEATED OXYGEN SENSOR-2,
V)
It indicates output voltage of HO2S-2 installed on
exhaust pipe (post-catalyst). It is used to detect catalyst
deterioration.
O2S B1 S2 ACT (HEATED OXYGEN SENSOR-2,
ACTIVE / INACTIVE)
This parameter indicates acti vation condition of HO2S-2.
ACTIVE: Activating
INACTIVE: warming up or at stop
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air/fuel ratio feedback loop status displayed as one of
the followings.
OPEN: Open-loop has not yet satisfied conditions to go
closed loop.
CLOSED: Closed-loop using oxygen sensor(s) as
feedback for fuel control.
OPEN-DRIVE COND: Open-loop due to driving
conditions (Power enrichment, etc.).
OPEN SYS FAULT: Open-loop due to detected system
fault.
MAP (MANIFOLD ABSOLUTE PRESSURE, in.Hg,
kPa)
This value indicates how much correction is necessary
to keep the air/fuel mixture stoichiometrical.
It is detected by manifold absolute pressure sensor.
BAROMETRIC PRESS (kPa, in.Hg)
This parameter represents a measurement of barometric
air pressure and is used for al titude correction of the fuel
injection quantity and IAC valve control.
STEP EGR FLOW DUTY (%)
This parameter indicates opening rate of EGR valve
which controls the amount of EGR flow.
FUEL CUT (ON/OFF)
ON: Fuel being cut (output signal to injector is stopped)
OFF: Fuel not being cut
A/C PRESSURE (A/C REFRIGERANT ABSOLUTE
PRESSURE, kPa)
This parameter indicates A/C refrigerant absolute
pressure calculated by ECM.
CLOSED THROTTLE PO S (CLOSED THROTTLE
POSITION, ON/OFF)
This parameter reads ON wh en throttle valve is fully
closed, or OFF when it is not fully closed. CANIST PRG DUTY (EVAP CANISTER PURGE FLOW
DUTY, %)
This parameter indicates valve ON (valve open) time
rate within a certain set cycle of EVAP canister purge
valve which controls the amount of EVAP purge.
IGNITION ADVANCE (IGNITION TIMING ADVANCE
FOR NO.1 CYLINDER,
°)
Ignition timing of No.1 cylinder is commanded by ECM.
The actual ignition timing should be checked by using
the timing light.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage
inputted from main relay to ECM.
FUEL PUMP (ON/OFF)
ON is displayed when ECM activates the fuel pump via
the fuel pump relay switch.
ELECTRIC LOAD (ON/OFF)
ON: Headlight or small light ON signal inputted.
OFF: Above electric loads all turned OFF.
BRAKE SW (ON/OFF)
This parameter indicates the state of the brake switch.
RADIATOR COOLING FAN (RADIATOR COOLING
FAN CONTROL RELAY, ON/OFF)
ON: Command for radiator cooling fan control relay
operation being output.
OFF: Command for relay operation not being output.
BLOWER FAN (ON/OFF)
This parameter indicates the state of the blower fan
motor switch.
A/C SWITCH (ON/OFF)
ON: Command for A/C operatio n being output from ECM
to HVAC.
OFF: Command for A/C oper ation not being output.
A/C COMP RELAY (A/C COMPRESSOR RELAY, ON/
OFF)
This parameter indicates the state of the A/C switch.
VEHICLE SPEED (km/h, mph)
It is computed based on pulse signals from vehicle
speed sensor.
VVT GAP (TARGET-ACTUAL POSITION, °)
It is calculated using the formula: target valve timing
advance – actual valve timing advance.
TP SENSOR 1 VOLT (THROTTLE POSITION SENSOR
(MAIN) OUTPUT VOLTAGE, V)
The TP sensor (main) reading provides throttle valve
opening information in the form of voltage.

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-41
Engine Symptom DiagnosisS7RS0B1104010
Perform troubleshooting referring to the followings when ECM has detected no DTC and no abnormality has been
found in “Visual Inspection” and “Engine Basic Inspection”.
Condition Possible cause Correction / Reference Item
Hard starting (Engine
cranks OK) Faulty spark plug
“Spark Plug Inspection in Section 1H”
Leaky high-tension cord “High-Tension Cord Inspection in Section 1H”
Loose connection or disconnection of
high-tension cord(s) or lead wire(s) “High-Tension Cord Removal and Installation
in Section 1H”
Faulty ignition coil “Ignition Coil Assembly (Including ignitor)
Inspection in Section 1H”
Dirty or clogged fuel hose or pipe “Fuel Pressure Check”
Malfunctioning fuel pump “Fuel Pressure Check”
Air drawn in through intake manifold
gasket or throttle body gasket
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty ECT sensor or MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty ECM
Low compression “Compression Check in Section 1D”
Poor spark plug tightening or faulty
gasket “Spark Plug Removal and Installation in
Section 1H”
Compression leak from valve seat “Valves and Valve Guides Inspection in
Section 1D”
Sticky valve stem “Valves and Valve Guides Inspection in
Section 1D”
Weak or damaged valve springs “Valve Spring Inspection in Section 1D”
Compression leak at cylinder head
gasket “Cylinder Head Inspection in Section 1D”
Sticking or damaged piston ring “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston, ring or cylinder “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Malfunctioning PCV valve “PCV Valve Inspection in Section 1B”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Faulty EGR system “EGR System Inspection in Section 1B”
Low oil pressure Improper oil viscosity “Engine Oil and Filter Change in Section 0B”
Malfunctioning oil pressure switch “Oil Pressure Switch Inspection in Section 9C”
Clogged oil strainer “Oil Pan and Oil Pump Strainer Cleaning in
Section 1E”
Functional deterioration of oil pump “Oil Pump Inspection in Section 1E”
Worn oil pump relief valve “Oil Pump Inspection in Section 1E”
Excessive clearance in various sliding
parts
Engine noise – Valve
noise
NOTE
Before checking
mechanical noise, make
sure that:
• Specified spark plug is used.
• Specified fuel is used.

Improper valve lash “Camshaft, Tappet and Shim Inspection in
Section 1D”
Worn valve stem and guide “Valves and Valve Guides Inspection in
Section 1D”
Weak or broken valve spring “Valve Spring Inspection in Section 1D”
Warped or bent valve “Valves and Valve Guides Inspection in
Section 1D”

Downloaded from www.Manualslib.com manuals search engine 1A-42 Engine General Information and Diagnosis:
Engine noise – Piston,
ring and cylinder noise
NOTE
Before checking
mechanical noise, make
sure that:
• Specified spark plug is used.
• Specified fuel is used.

Worn piston, ring and cylinder bore “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Engine noise –
Connecting rod noise
NOTE
Before checking
mechanical noise, make
sure that:
• Specified spark plug is used.
• Specified fuel is used.

Worn piston, ring and cylinder bore “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn rod bearing “Crank Pin and Connecting Rod Bearings
Inspection in Section 1D”
Worn crank pin “Crank Pin and Connecting Rod Bearings
Inspection in Section 1D”
Loose connecting rod nuts “Pistons, Piston Rings, Connecting Rods and
Cylinders Removal and Installation in Section
1D”
Low oil pressure Condition “Low oil pressure”
Engine noise –
Crankshaft noise
NOTE
Before checking
mechanical noise, make
sure that:
• Specified spark plug is used.
• Specified fuel is used.

Low oil pressure Condition “Low oil pressure”
Worn bearing “Main Bearings Inspection in Section 1D”
Worn crankshaft journal “Crankshaft Inspection in Section 1D”
Loose bearing cap bolts “Main Bearings, Crankshaft and Cylinder Block
Removal and Installation in Section 1D”
Excessive crankshaft thrust play “Crankshaft Inspection in Section 1D”
Engine overheating Inoperative thermostat “Thermostat Inspection in Section 1F”
Poor water pump performance “Water Pump Inspection in Section 1F”
Clogged or leaky radiator “Radiator On-Vehicle Inspection and Cleaning
in Section 1F”
Improper engine oil grade “Engine Oil and Filter Change in Section 0B”
Clogged oil filter or oil strainer “Oil Pressure Check in Section 1E”
Poor oil pump performance “Oil Pressure Check in Section 1E”
Faulty radiator cooling fan control
system “Radiator Cooling Fan Low Speed Control
System Check” or “Rad
iator Cooling Fan High
Speed Control System Check”
Dragging brakes Condition “Dragging brakes” in “Brakes
Symptom Diagnosis in Section 4A”
Slipping clutch Condition “Slipping clutch” in “Clutch System
Symptom Diagnosis in Section 5C”
Blown cylinder head gasket “Cylinder Head Inspection in Section 1D”
Air mixed in cooling system
Condition Possible cause Correction / Reference Item

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-43
Poor gasoline mileageLeaks or loose connection of high-
tension cord “High-Tension Cord Removal and Installation
in Section 1H”
Faulty spark plug (improper gap, heavy
deposits and burned electrodes, etc.) “Spark Plug Inspection in Section 1H”
Malfunctioning EGR valve “EGR Valve Inspection in Section 1B”
High idle speed Condition “Improper engine idling or engine
fails to idle”
Poor performance of ECT sensor or
MAF sensor “ECT Sensor Inspection in Section 1C” or
“MAF and IAT Sensor Inspection in Section
1C”
Faulty electric throttle body assembly “Electric Throttle Body Assembly On-Vehicle
Inspection in Section 1C”
Faulty APP sensor assembly “APP Sensor Assembly Inspection in Section
1C”
Faulty fuel injector(s) “Fuel Injector Circuit Check”
Faulty ECM
Low compression “Compression Check in Section 1D”
Poor valve seating “Valves and Valve Guides Inspection in
Section 1D”
Dragging brakes Condition “Dragging brakes” in “Brakes
Symptom Diagnosis in Section 4A”
Slipping clutch Condition “Slipping clutch” in “Clutch System
Symptom Diagnosis in Section 5C”
Thermostat out of order “Thermostat Inspection in Section 1F”
Improper tire pressure “Tires Description in Section 2D”
Camshaft position control (VVT) system
out of order “Oil Control Valve Inspection in Section 1D”
Excessive engine oil
consumption – Oil
leakage Blown cylinder head gasket
“Cylinder Head Inspection in Section 1D”
Leaky camshaft oil seals “Camshaft, Tappet and Shim Inspection in
Section 1D”
Excessive engine oil
consumption – Oil
entering combustion
chamber Sticky piston ring
“Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston and cylinder “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Worn piston ring groove and ring “Cylinders, Pistons and Piston Rings
Inspection in Section 1D”
Improper location of piston ring gap “Pistons, Piston Rings, Connecting Rods and
Cylinders Disassembly and Assembly in
Section 1D”
Worn or damaged valve stem seal “Valves and Valve Guides Inspection in
Section 1D”
Worn valve stem “Valves and Valve Guides Inspection in
Section 1D”
Condition Possible cause Correction / Reference Item