fuel pressure INFINITI QX56 2009 Factory Owner's Manual

EC-164
< COMPONENT DIAGNOSIS >[VK56DE]
P0139, P0159 HO2S2
P0139, P0159 HO2S2
Component DescriptionINFOID:0000000003771427
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of
the air fuel ratio (A/F) sensor 1
are shifted, the air-fuel ratio is cont rolled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated ox ygen sensor 2 is not used for
engine control operation.
On Board Diagn osis LogicINFOID:0000000003771428
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000003771429
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
WITH CONSULT-III
TESTING CONDITION:
For better results, perform “DTC WORK SU PPORT” at a temperature of 0 to 30 °C (32 to 86 °F).
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S” indicates more than 70 °C (158 °F).
SEF327R
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139
(Bank 1) Heated oxygen sensor 2
circuit slow response It takes more time for the sensor to respond be-
tween rich and lean than the specified time.  Harness or connectors
(The sensor circuit is open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0159
0159
(Bank 2)
Revision: December 20092009 QX56

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-169
< COMPONENT DIAGNOSIS > [VK56DE]
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D
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G H
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K L
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EC
NP
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P0171, P0174 FUEL INJE
CTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000003771433
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000003771434
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC. The 1st trip DTC P0171 or P0174 should be detected at this stage, if a malfunction exists. If so, go to EC-
170, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar condi tions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel injection control Fuel injector
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0171
0171
(Bank 1) Fuel injection system too
lean  Fuel injection system does not operate properly.
 The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.)  Intake air leaks
 A/F sensor 1
 Fuel injector
 Exhaust gas leaks
 Incorrect fuel pressure
 Lack of fuel
 Mass air flow sensor
 Incorrect PCV hose connection
P0174
0174
(Bank 2)
Engine speed Engine speed in the freeze frame data
± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Revision: December 20092009 QX56

EC-172
< COMPONENT DIAGNOSIS >[VK56DE]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
6. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-487, "Fuel Pressure Check"
.
2. Install fuel pressure gauge kit [SST (J -44321)] and check fuel pressure. Refer to EC-487, "Fuel Pressure
Check".
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
 Fuel pump and circuit (Refer to EC-395, "Diagnosis Procedure"
.)
 Fuel pressure regulator (Refer to EC-487, "Fuel Pressure Check"
.)
 Fuel lines
 Fuel filter for clogging
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK >> GO TO 7.
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
grounds. Refer to EC-103
.
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Make sure that each circuit produces a momentary engine speed drop.
Without CONSULT-III
1. Start engine. At idling: Approximately 350 kPa (3.57 kg/cm
2, 51 psi)
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
Revision: December 20092009 QX56

EC-174
< COMPONENT DIAGNOSIS >[VK56DE]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
P0172, P0175 FUEL INJE
CTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000003771436
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000003771437
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC. The 1st trip DTC P0172, P0175 should be detected at th is stage, if a malfunction exists. If so, go to EC-
175, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min- utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel injection control Fuel injector
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0172
0172
(Bank 1) Fuel injection system too
rich  Fuel injection system does not operate properly.
 The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.)  A/F sensor 1
 Fuel injector
 Exhaust gas leaks
 Incorrect fuel pressure
 Mass air flow sensor
P0175
0175
(Bank 2)
Engine speed Engine speed in the freeze frame data
± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Revision: December 20092009 QX56

P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-177
< COMPONENT DIAGNOSIS > [VK56DE]
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EC
NP
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OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-487, "Fuel Pressure Check"
.
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-487, "Fuel Pressure Check"
.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
 Fuel pump and circuit (Refer to EC-395, "Diagnosis Procedure"
.)
 Fuel pressure regulator (Refer to EC-487, "Fuel Pressure Check"
.)
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK >> GO TO 7.
NG >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
grounds. Refer to EC-103
.
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Make sure that each circuit produces a momentary engine speed drop.
Without CONSULT-III
1. Start engine. At idling: Approximately 350 kPa (3.57 kg/cm
2, 51 psi)
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
Revision: December 20092009 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-189
< COMPONENT DIAGNOSIS > [VK56DE]
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EC
NP
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P0300, P0301, P0302, P0303, P0304,
P0305, P0306, P0307, P0308 MIS-
FIRE
On Board Diagnosis LogicINFOID:0000000003771454
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, when a misfire condition occurs that can damage the three way catalyst (TWC) due to
overheating, the MIL 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 t hat will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level t hat will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL 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 MIL will only
light when the misfire is detected on a second trip. Du ring this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
DTC Confirmation ProcedureINFOID:0000000003771455
CAUTION:
Always drive vehicle in safe manner according to traf fic conditions and obey all traffic laws when driv-
ing.
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
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
0300 Multiple cylinder misfire
detected
Multiple cylinder misfire.
 Improper spark plug
 Insufficient compression
 Incorrect fuel pressure
 The injector circuit is open or shorted
 Fuel injector
 Intake air leak
 The ignition signal circuit is open or short-ed
 Lack of fuel
 Signal plate
 Air fuel ratio (A/F) sensor 1
 Incorrect PCV hose connection
P0301
0301
No.1 cylinder misfire de-
tected
No. 1 cylinder misfires.
P0302
0302 No. 2 cylinder misfire
detected
No. 2 cylinder misfires.
P0303
0303 No. 3 cylinder misfire
detected
No. 3 cylinder misfires.
P0304
0304 No. 4 cylinder misfire
detected
No. 4 cylinder misfires.
P0305
0305 No. 5 cylinder misfire
detected
No. 5 cylinder misfires.
P0306
0306 No. 6 cylinder misfire
detected
No. 6 cylinder misfires.
P0307
0307 No. 7 cylinder misfire
detected
No. 7 cylinder misfires.
P0308
0308 No. 8 cylinder misfire
detected
No. 8 cylinder misfires.
Revision: December 20092009 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-191
< COMPONENT DIAGNOSIS > [VK56DE]
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G H
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EC
NP
O
When disconnecting each fuel injector harness connector
one at a time, is there any cylinder which does not
produce a momentary engine speed drop?
Ye s o r N o
Yes >> GO TO 4.
No >> GO TO 7.
4.CHECK FUEL INJECTOR
Does each fuel injector make an operating sound at idle?
Ye s o r N o
Yes >> GO TO 5.
No >> Check fuel injector(s) and circuit(s). Refer to EC-392,
"Diagnosis Procedure".
5.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
11. Crank engine for about 3 seconds, and check whether spark is
generated between the spark plug and the grounded metal por-
tion.
CAUTION:
BBIA0374E
PBIB1986E
Spark should be generated.
BBIA0380E
PBIB2325E
Revision: December 20092009 QX56

EC-192
< COMPONENT DIAGNOSIS >[VK56DE]
P0300, P0301, P0302, P
0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
 Do not approach to the spark pl ug and the ignition coil within 50cm. Be careful not to get an
electrical shock while checking, because the electrical discharge voltage becomes 20kV or
more.
 It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
OK or NG
OK >> GO TO 9.
NG >> GO TO 6.
6.CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug.
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
OK or NG
OK >> GO TO 7.
NG >> Check ignition coil, power transistor and their circuits. Refer to EC-404, "Diagnosis Procedure"
.
7.CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
OK or NG
OK >> Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to EM-16, "Removal
and Installation".
NG >> 1. Repair or clean spark plug.
2. GO TO 8.
8.CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.
OK or NG
OK >> INSPECTION END
NG >> Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to EM-
16, "Removal and Installation".
9.CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM-23, "Checking Compression Pressure"
.
OK or NG
OK >> GO TO 10.
NG >> Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
10.CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-487, "Fuel Pressure Check"
.
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-487, "Fuel Pressure Check"
.
Spark should be generated.
SEF156I
Spark should be generated.
At idling: Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)
Revision: December 20092009 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-193
< COMPONENT DIAGNOSIS > [VK56DE]
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G H
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EC
NP
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OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
11 .DETECT MALFUNCTIONING PART
Check the following.
 Fuel pump and circuit (Refer to EC-395, "Diagnosis Procedure"
.)
 Fuel pressure regulator (Refer to EC-487, "Fuel Pressure Check"
.)
 Fuel lines
 Fuel filter for clogging
>> Repair or replace.
12.CHECK IGNITION TIMING
Check the following items. Refer to EC-13, "Basic Inspection"
.
OK or NG
OK >> GO TO 13.
NG >> Follow the EC-13, "Basic Inspection"
.
13.CHECK A/F SENSOR 1 INPUT SIGNAL
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5 ° BTDC (in P or N position)
A/F sensor 1 terminal ECM terminal
Bank 1 135
256
Bank 2 116
275
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 135116
256275
BBIA0376E
Revision: December 20092009 QX56

EC-208
< COMPONENT DIAGNOSIS >[VK56DE]
P0420, P0430 THREE
WAY CATALYST FUNCTION
Check the following items. Refer to EC-13, "Basic Inspection".
OK or NG
OK >> GO TO 5.
NG >> Follow the EC-13, "Basic Inspection"
.
5.CHECK FUEL INJECTOR
1. Stop engine and then turn ignition switch ON.
2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42, 44, 63 and ground with CONSULT-III or tester.
Refer to Wiring Diagram for fuel injector, EC-432, "Wiring Dia-
gram - ENGINE CONTROL SYSTEM -".
OK or NG
OK >> GO TO 6.
NG >> Perform EC-404, "Diagnosis Procedure"
.
6.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-III to releas e fuel pressure, or fuel pres-
sure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electri-
cal discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
11. Crank engine for about 3 seconds, and check whether spark is
generated between the spark plug and the grounded metal por-
tion.
CAUTION:
 Do not approach to the spar k plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the el ectrical discharge voltage
becomes 20kV or more.
 It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
OK or NG
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5 ° BTDC (in P or N position)
Battery voltage should exist.
PBIB1527E
Spark should be generated.
BBIA0380E
PBIB2325E
Revision: December 20092009 QX56