EC-120
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
*: This item is not used on this vehicle.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
SET LAMP ON/OFF Indicates [ON/OFF] condition of SET lamp deter-
mined by the ECM according to the input signals.
BAT CUR SEN mV The signal voltage of battery current sensor is
displayed.
ALT DUTY SIG ON/OFF The control condition of the power generation
voltage variable control (determined by ECM ac-
cording to the input signals) is indicated.
ON: Power generation voltage variable control is
active.
OFF: Power generation voltage variable control
is inactive.
A/F ADJ-B1
— Indicates the correction of factor stored in ECM.
The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and
the air-fuel ratio calculated from A/F sensor 1 sig-
nal. A/F ADJ-B2
ALT DUTY % Indicates the duty ratio of the power generation
command value. The ratio is calculated by ECM
based on the battery current sensor signal. Monitored item Unit Description Remarks
TEST ITEM CONDITION JUDGMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION Engine: Return to the original
non-standard condition
Change the amount of fuel injec-
tion using CONSULT-III.If malfunctioning symptom disap-
pears, see CHECK ITEM. Harness and connectors
Fuel injector
Air fuel ratio (A/F) sensor 1
IGNITION TIM-
ING Engine: Return to the original
non-standard condition
Timing light: Set
Retard the ignition timing using
CONSULT-III.If malfunctioning symptom disap-
pears, see CHECK ITEM. Perform Idle Air Volume Learning.
POWER BAL-
ANCE Engine: After warming up, idle the
engine.
A/C switch OFF
Selector lever: P or N
Cut off each injector signal one at
a time using CONSULT-III.Engine runs rough or dies. Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
COOLING FAN*
1
Ignition switch: ON
Turn the cooling fan “HI”, “MID”,
“LOW” and “OFF” using CON-
SULT-III.Cooling fan moves and stops. Harness and connectors
Cooling fan motor
IPDM E/R
ENG COOLANT
TEMP Engine: Return to the original
non-standard condition
Change the engine coolant tem-
perature using CONSULT-III.If malfunctioning symptom disap-
pears, see CHECK ITEM. Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
FUEL PUMP RE-
LAY Ignition switch: ON (Engine
stopped)
Turn the fuel pump relay “ON”
and “OFF” using CONSULT-III
and listen to operating sound.Fuel pump relay makes the operat-
ing sound. Harness and connectors
Fuel pump relay
P0300, P0301, P0302, P0303, P0304, P0305, P0306 MISFIRE
EC-209
< COMPONENT DIAGNOSIS >[VQ25DE, VQ35DE]
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P0300, P0301, P0302, P0303, P0304, P0305, P0306 MISFIRE
DTC LogicINFOID:0000000003856617
DTC DETECTION LOGIC
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage)
On the 1st trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MI will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MI will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MI will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MI will remain on.
If another misfire condition occurs that can damage the TWC, the MI will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration)
For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MI will only light
when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sensor
signal every 1,000 engine revolutions.
A misfire malfunction can be detected in any one cylinder or in multiple cylinders.
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Restart engine and let it idle for about 15 minutes.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-210, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Turn ignition switch OFF and wait at least 10 seconds.
Sensor Input signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300 Multiple cylinder misfires detected Multiple cylinder misfire. Improper spark plug
Insufficient compression
Incorrect fuel pressure
The fuel injector circuit is open or shorted
Fuel injector
Intake air leak
The ignition signal circuit is open or shorted
Lack of fuel
Signal plate
A/F sensor 1
Incorrect PCV hose connection P0301 No.1 cylinder misfire detected No. 1 cylinder misfires.
P0302 No. 2 cylinder misfire detected No. 2 cylinder misfires.
P0303 No. 3 cylinder misfire detected No. 3 cylinder misfires.
P0304 No. 4 cylinder misfire detected No. 4 cylinder misfires.
P0305 No. 5 cylinder misfire detected No. 5 cylinder misfires.
P0306 No. 6 cylinder misfire detected No. 6 cylinder misfires.
EM-1
ENGINE
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SECTION EM
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CONTENTS
ENGINE MECHANICAL
SYMPTOM DIAGNOSIS ...............................3
NOISE, VIBRATION AND HARSHNESS
(NVH) TROUBLESHOOTING .............................
3
NVH Troubleshooting - Engine Noise .......................3
Use the Chart Below to Help You Find the Cause
of the Symptom .........................................................
4
PRECAUTION ...............................................5
PRECAUTIONS ...................................................5
Precaution for Procedure without Cowl Top Cover ......5
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
5
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
5
Precaution for Drain Engine Coolant and Engine
Oil ..............................................................................
6
Precaution for Disconnecting Fuel Piping .................6
Precaution for Removal and Disassembly ................6
Precaution for Inspection, Repair and Replace-
ment ..........................................................................
6
Precaution for Assembly and Installation ..................6
Precaution for Angle Tightening ................................6
Precaution for Liquid Gasket .....................................7
PREPARATION ............................................8
PREPARATION ...................................................8
Special Service Tool .................................................8
Commercial Service Tool ..........................................9
ON-VEHICLE MAINTENANCE ....................12
DRIVE BELT .......................................................12
Exploded View ........................................................12
Checking .................................................................12
Tension Adjustment ................................................12
Removal and Installation .........................................12
AIR CLEANER FILTER ......................................14
Removal and Installation .........................................14
SPARK PLUG ...................................................15
Exploded View .........................................................15
Removal and Installation .........................................15
Inspection ................................................................16
CAMSHAFT VALVE CLEARANCE ..................17
Inspection and Adjustment ......................................17
COMPRESSION PRESSURE ...........................22
Inspection ................................................................22
ON-VEHICLE REPAIR .................................24
ENGINE COVER ...............................................24
Exploded View .........................................................24
Removal and Installation .........................................24
DRIVE BELT AUTO TENSIONER AND IDLER
PULLEY .............................................................
25
Exploded View .........................................................25
Removal and Installation .........................................25
AIR CLEANER AND AIR DUCT .......................26
Exploded View .........................................................26
Removal and Installation .........................................26
Inspection ................................................................27
INTAKE MANIFOLD COLLECTOR ..................28
Exploded View .........................................................28
Removal and Installation .........................................29
INTAKE MANIFOLD .........................................32
Exploded View .........................................................32
Removal and Installation .........................................32
Inspection ................................................................33
EXHAUST MANIFOLD AND THREE WAY
CATALYST ........................................................
34
Exploded View .........................................................34
Removal and Installation .........................................34
Inspection ................................................................37
EM-10
< PREPARATION >
PREPARATION
(—)
Manual lift table caddyRemoving and installing engine
(J24239-01)
Cylinder head bolt wrenchLoosening and tightening cylinder head bolt,
and used with the angle wrench [SST:
KV10112100 (BT8653-A)]
a: 13 mm (0.51 in) dia.
b: 12 mm (0.47 in)
c: 10 mm (0.39 in)
(—)
1.Compression tester
2.AdapterChecking compression pressure
(—)
Spark plug wrenchRemoving and installing spark plug
a: 14 mm (0.55 in)
(—)
Pulley holderRemoving and installing crankshaft pulley
(—)
Valve seat cutter setFinishing valve seat dimensions
(—)
Piston ring expanderRemoving and installing piston ring (SPX North America No.)
Tool nameDescription
ZZA1210D
NT583
ZZA0008D
JPBIA0399ZZ
ZZA1010D
NT048
NT030
SERVICE DATA AND SPECIFICATIONS (SDS)
EM-135
< SERVICE DATA AND SPECIFICATIONS (SDS)
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SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
General SpecificationINFOID:0000000003802300
GENERAL SPECIFICATIONS
EngineVQ25DE VQ35DE
Cylinder arrangementV- 6
Displacement cm
3 (cu in)2,495 (152.24) 3,498 (213.45)
Bore and stroke mm (in)85.0 x 73.3
(3.346 x 2.886)95.5 x 81.4
(3.760 x 3.205)
Valve arrangementDOHC
Firing order1-2-3-4-5-6
Number of piston ringsCompression 2
Oil 1
Number of main bearings4
Compression ratio9.8 10.3
Compression pressure
kPa (bar, kg/cm
2, psi)/300 rpmStandard 1,275 (12.8, 13.0, 185)
Minimum 981 (9.8, 10.0, 142)
Differential limit between cylinders 98 (1.0, 1.0, 14)
Cylinder number
Valve timing
(Valve timing control - “OFF”)
Unit: degree
ab c d e f
VQ25DE 240 244−658852
VQ35DE 240 260−10 70 10 50
SEM713A
PBIC0187E