Page 1950 of 2453

ME(H6DO)-84
Engine Trouble in General
MECHANICAL
3) Initial combustion occurs. Engine control system A
Intake system Defective intake manifold gasket B
Defective throttle body gasket B
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Chain Trouble B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plug or defective gasket C
Loosened cylinder head bolt or defective gasket C
Improper valve sealing C
Defective valve stem C
Wor n or broken valve spr ing B
Wor n or stuck piston r ings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
4) Engine stalls after initial
combustion.
Engine control system A
Intake system Loosened or cracked intake duct B
Loosened or cracked PCV hose C
Loosened or cracked vacuum hose C
Defective intake manifold gasket B
Defective throttle body gasket B
Dirty air cleaner element C
Fuel line Clogged fuel line C
Lack of or insufficient fuel B
Chain Trouble B
Defective timing B
Compression Incorrect valve clearance C
Loosened spark plug or defective gasket C
Loosened cylinder head bolt or defective gasket C
Improper valve sealing C
Defective valve stem C
Wor n or broken valve spr ing B
Wor n or stuck piston r ings, cylinder and piston C
Incorrect valve timing B
Improper engine oil (low viscosity) B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
Symptom Problem parts etc. Possible cause RANK
Page 1951 of 2453

ME(H6DO)-85
Engine Trouble in General
MECHANICAL
2. Rough idle and engine
stall
Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve C
Loosened oil filler cap B
Dirty air cleaner element C
Fuel line Defective fuel pump and relay C
Clogged fuel line C
Lack of or insufficient fuel B
Chain Defective timing C
Compression Incorrect valve clearance B
Loosened spark plug or defective gasket B
Loosened cylinder head bolt or defective gasket B
Improper valve sealing B
Defective valve stem C
Wor n or broken valve spr ing B
Wor n or stuck piston r ings, cylinder and piston B
Incorrect valve timing A
Improper engine oil (low viscosity) B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
Lubrication system Incorrect oil pressure B
Defective rocker cover gasket C
Cooling system Over-heating C
Others Evaporative emission control system malfunction A
Stuck or damaged throttle valve B
Symptom Problem parts etc. Possible cause RANK
Page 1952 of 2453

ME(H6DO)-86
Engine Trouble in General
MECHANICAL
3. Low output, hesitation and
poor acceleration
Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose B
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element A
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Chain Defective timing B
Compression Incorrect valve clearance B
Loosened spark plug or defective gasket B
Loosened cylinder head bolt or defective gasket B
Improper valve sealing B
Defective valve stem C
Wor n or broken valve spr ing B
Wor n or stuck piston r ings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
Lubrication system Incorrect oil pressure B
Cooling system Over-heating C
Over-cooling C
Others Evaporative emission control system malfunction A
Symptom Problem parts etc. Possible cause RANK
Page 1953 of 2453

ME(H6DO)-87
Engine Trouble in General
MECHANICAL
4. Surging Engine control system A
Intake system Loosened or cracked intake duct A
Loosened or cracked PCV hose A
Loosened or cracked vacuum hose A
Defective intake manifold gasket B
Defective throttle body gasket B
Defective PCV valve B
Loosened oil filler cap B
Dirty air cleaner element B
Fuel line Defective fuel pump and relay B
Clogged fuel line B
Lack of or insufficient fuel C
Chain Defective timing B
Compression Incorrect valve clearance B
Loosened spark plug or defective gasket C
Loosened cylinder head bolt or defective gasket C
Improper valve sealing C
Defective valve stem C
Wor n or broken valve spr ing C
Wor n or stuck piston r ings, cylinder and piston C
Incorrect valve timing A
Improper engine oil (low viscosity) B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
Cooling system Over-heating B
Others Evaporative emission control system malfunction C
5. Engine does not return to
idle.
Engine control system A
Intake system Loosened or cracked vacuum hose A
Others Stuck or damaged throttle valve A
6. Dieseling (Run-on) Engine control system A
Cooling system Over-heating B
Others Evaporative emission control system malfunction B
Symptom Problem parts etc. Possible cause RANK
Page 1955 of 2453
ME(H6DO)-89
Engine Trouble in General
MECHANICAL
10. Excessive fuel consump-
tion
Engine control system A
Intake system Dirty air cleaner element A
Chain Defective timing B
Compression Incorrect valve clearance B
Loosened spark plug or defective gasket C
Loosened cylinder head bolt or defective gasket C
Improper valve sealing B
Defective valve stem C
Wor n or broken valve spr ing C
Wor n or stuck piston r ings, cylinder and piston B
Incorrect valve timing B
Tr o u b l e o f t a p p e t C
Tr o u b l e o f t a p p e t . I n c a s e n o i s e o c c u r s w i t h v a l v e m o v -
ing. Or the harness involved to oil switching solenoid
valve, variable valve lift diagnosis oil pressure switch
and variable valve lift has trouble in a past.
B
Lubrication system Incorrect oil pressure C
Cooling system Over-cooling C
Symptom Problem parts etc. Possible cause RANK
Page 1956 of 2453

ME(H6DO)-90
Engine Noise
MECHANICAL
29.Engine Noise
A: INSPECTION
(NOTE*)
When disconnecting the fuel injector connector, the malfunction indicator light illuminates and DTC is stored in ECM memory.
Therefore, carry out the clear memory mode and inspection
mode after connecting the fuel injector connector.
Ty p e o f s o u n d C o n d i t i o n P o s s i b l e c a u s e
Regular clicking soundSound increases as engine
speed increases.
•Valve mechanism is defective.
•Incorrect valve clearance
•Worn valve rocker
•Worn camshaft
•Broken valve spring
•Trouble of tappet
Heavy and dull clankOil pressure is low.•Worn camshaft main bearing
•Worn connecting rod bearing (large end)
Oil pressure is normal. Damaged engine mounting
High-pitched clank
Sound is noticeable when
accelerating with an overload
condition.
•Ignition timing advanced
•Accumulation of carbon inside combustion chamber
•Wrong spark plug
•Improper gasoline
Clank when engine speed is
between 1,000 and 2,000
rpms.
Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*)
•Worn crankshaft main bearing
•Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warm
Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*)
•Worn cylinder liner and piston ring
•Broken or stuck piston ring
•Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is dis-
connected in turn. (NOTE*)
•Unusually worn valve lifter
•Worn cam gear
•Worn camshaft journal bore in crankcase
Squeaky sound — • Insufficient generator lubrication
Rubbing sound — • Poor contact of generator brush and rotor
Gear scream when starting
engine—•Defective ignition starter switch
•Worn gear and starter pinion
Sound like polishing glass with
a dry cloth—•Loose drive belt
•Defective water pump shaft
Hissing sound —•Insufficient compression
•Air leakage in air intake system, hose, connection or manifold
Timing belt noise —•Loose timing belt
•Belt contacting with case/adjacent part
Va l ve t a p p e t n o i s e —•Incorrect valve clearance
•Trouble of tappet
Page 2297 of 2453
WI-13
Basic Diagnostic Procedure
WIRING SYSTEM
F: ABBREVIATION IN WIRING DIA-
GRAMS
Abbr. Full name
A/C Air conditioner
A/FAir/Fuel
(Air fuel ratio sensor)
ABS Anti-lock Brake System
ACC Accessor y
AT E l e c t r o n i c a l l y c o n t r o l l e d f u l l y - a u t o m a t i c
AUX Auxiliar y
AW D A ll W he e l D r i ve
CAN Controller Area Network
CPC Canister Purge Control
CPU Central Processing Unit
ECM Engine Control Module (ECM)
EEPROMElectronically Erasable and Programma-
ble Read Only Memory
F/B Fuse & Relay box
FWD Front Wheel Drive
H/L Headlight
I/F Interface
IG Ignition
L, LH Left Hand
LCD Liquid Crystal Display
M/B Main fuse box
MFD Multi Function Display
OP Optional Parts or Open
PWM Pulse Width Modulation
R, RH Right Hand
SBF Slow Blow Fuse
ST Starter
TCS Traction Control System
TCM AT Control Module
TPM Tire Pressure Monitor
TV Television
U, UP Up
VDC Vehicle Dynamics Control
VVL Variable Valve Lift
Page 2305 of 2453
WI-21
Power Supply Circuit
WIRING SYSTEM
FB-37 Body integrated unit
FB-38 ECM
TCM
Fuel pump relay
FB-39 Airbag control module
FB-41 Airbag control module
FB-42 Power window relay
FB-44 VDC control module
Steering angle sensor
Ya w r a t e s e n s o r
FB-45 A/C control panel
Rear cooler relay
FB-46 A/C relay
FRESH/RECIRC actuator
Auto A/C control module
Pressure switch
Blower fan relay
FB-47 Occupant detection control module
FB-48 TPM control module
FB-49 Impact sensor
TV monitor
ACC -1 Front washer motor
ST-1 ECM
Starter relay
No. Load