2009 INFINITI QX56 engine

FUEL PUMPEC-395
< COMPONENT DIAGNOSIS > [VK56DE]
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FUEL PUMP
DescriptionINFOID:0000000003771715
SYSTEM DESCRIPTION
*: ECM determines the start signal status by the signals of engine speed and battery voltage.
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine
startability. If the ECM receives a engine speed signal
from the camshaft position sensor (PHASE), it knows
that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when
the ignition switch is ON, the engine stalls. The EC M stops pump operation and prevents battery discharging,
thereby improving safety. The ECM does not directly dr ive the fuel pump. It controls the ON/OFF fuel pump
relay, which in turn controls the fuel pump.
COMPONENT DESCRIPTION
A turbine type design fuel pump is used in the fuel tank.
Diagnosis ProcedureINFOID:0000000003771716
1.CHECK OVERALL FUNCTION
1. Turn ignition switch ON.
2. Pinch fuel feed hose with two fingers.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Turn ignition switch ON.
Sensor Input signal to ECM ECM Function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed*
Fuel pump control Fuel pump relay
Battery Battery voltage*
Condition Fuel pump operation
Ignition switch is turned to ON. Operates for 1 second.
Engine running and cranking Operates.
When engine is stopped Stops in 1.5 seconds.
Except as shown above Sto ps .
BBIA0402E
Fuel pressure pulsation should be felt on the fuel feed
hose for 1 second after ignition switch is turned ON.
BBIA0357E
Revision: December 20092009 QX56

EC-404
< COMPONENT DIAGNOSIS >[VK56DE]
IGNITION SIGNAL
IGNITION SIGNAL
Component DescriptionINFOID:0000000003771721
IGNITION COIL & POWER TRANSISTOR
The ignition signal from the ECM is sent to and amplifi
ed by the power transistor. The power transistor turns
ON and OFF the ignition coil primary circuit. This ON/O FF operation induces the proper high voltage in the coil
secondary circuit.
Diagnosis ProcedureINFOID:0000000003771722
1.CHECK ENGINE START
Turn ignition switch OFF, and restart engine.
Is engine running?
Ye s o r N o
Yes (With CONSULT-IIl)>>GO TO 2.
Yes (Without CONSULT-lII)>>GO TO 3.
No >> GO TO 4.
2.CHECK OVERALL FUNCTION
With CONSULT-IIl
1. Perform “POWER BALANCE” in “ACTIVE TEST” mode with CONSULT-lII.
2. Make sure that each circuit produces a momentary engine speed drop.
OK or NG
OK >> INSPECTION END
NG >> GO TO 10.
3.CHECK OVERALL FUNCTION
Without CONSULT-IIl
1. Let engine idle.
2. Read the voltage signal between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ground with an oscilloscope.
3. Verify that the oscilloscope screen shows the signal wave as shown below.
NOTE:
The pulse cycle changes depending on rpm at idle.
OK or NG
1. Ignition coils (with power transistor) (bank 2) 2. Ignition coils (with power transistor)
(bank 1)
BBIA0777E
PBIB2094E
PBIB0044E
Revision: December 20092009 QX56

EC-408
< COMPONENT DIAGNOSIS >[VK56DE]
IGNITION SIGNAL
7. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-IIl to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
8. Start engine.
9. After engine stalls, crank it two or three times to release all fuel pressure.
10. Turn ignition switch OFF.
11. Remove all ignition coil harness connectors to avoid the electri-
cal discharge from the ignition coils.
12. Remove ignition coil and spark plug of the cylinder to be checked.
13. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
14. Connect spark plug and harness connector to ignition coil.
15. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.
16. 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 igni tion coil if the gap of more than 17 mm (0.66 in) is taken.
NOTE:
When the gap is less than 13 mm (0.52 in) , the sp ark might be generated even if the coil is mal-
functioning.
17. If NG, replace ignition coil with power transistor.
CONDENSER-1
1. Turn ignition switch OFF.
2. Disconnect condenser-1 harness connector.
3. Check resistance between condenser-1 terminals 1 and 2. Spark should be generated.
BBIA0380E
PBIB2325E
Resistance Above 1 M
Ω [at 25 °C (77 °F)]
PBIB0794E
Revision: December 20092009 QX56

ON BOARD REFUELING VAPOR RECOVERY (ORVR)EC-409
< COMPONENT DIAGNOSIS > [VK56DE]
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ON BOARD REFUELING VAPOR RECOVERY (ORVR)
System DescriptionINFOID:0000000003771724
From the beginning of refueling, the air and vapor insi
de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The v apor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspectio ns below, be sure to observe the following:
 Put a “CAUTION: FLAMMABLE” sign in workshop.
 Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.
 Be sure to furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
 Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-proof containe r and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-487, "Fuel Pressure Check"
.
- Disconnect battery ground cable.
 Always replace O-ring when the fu el gauge retainer is removed.
 Do not kink or twist hose and tube when they are installed.
 Do not tighten hose and clamps excessively to avoid damaging hoses.
 After installation, run engine a nd check for fuel leaks at connection.
 Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, r esulting in fuel spray and possibly a fire.
Diagnosis ProcedureINFOID:0000000003771725
SYMPTOM: FUEL ODOR FROM EVAP CANISTER IS STRONG.
1.CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent c ontrol valve and EVAP control system pressure sensor
attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be l ess than 2.5 kg (5.5 lb).
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK IF EVAP CANISTER SATURATED WITH WATER
PBIB1068E
Revision: December 20092009 QX56

EC-414
< COMPONENT DIAGNOSIS >[VK56DE]
POSITIVE CRANKCASE VENTILATION
POSITIVE CRANKCASE VENTILATION
DescriptionINFOID:0000000003771727
SYSTEM DESCRIPTION
This system returns blow-by gas to the intake manifold.
The positive crankcase ventilation (PCV) valve is prov
ided to conduct crankcase blow-by gas to the intake
manifold. During partial throttle operation of the engine, the intake manifold sucks the blow-by gas through the
PCV valve. Normally, the capacity of the valve is suff icient to handle any blow-by and a small amount of venti-
lating air. The ventilating air is drawn from the air inle t tubes into the crankcase. In this process the air passes
through the hose connecting air inlet tubes to rocker cover. Under full-throttle condition, the manifold vacuum
is insufficient to draw the blow-by flow through t he valve. The flow goes through the hose connection in the
reverse direction.
On vehicles with an excessively high blow-by, the valve does not
meet the requirement. This is because some of the flow will go
through the hose connection to the air inlet tubes under all condi-
tions.
Component InspectionINFOID:0000000003771728
PCV (POSITIVE CRANKCASE VENTILATION) VALVE
With engine running at idle, remove PCV valve from rocker cover. A
properly working valve makes a hissing noise as air passes through
it. A strong vacuum should be felt immediately when a finger is
placed over valve inlet.
PCV VALVE VENTILATION HOSE
PBIB0062E
PBIB1588E
PBIB1589E
Revision: December 20092009 QX56

EC-416
< COMPONENT DIAGNOSIS >[VK56DE]
REFRIGERANT PRESSURE SENSOR
REFRIGERANT PRESSURE SENSOR
Component DescriptionINFOID:0000000003771729
The refrigerant pressure sensor is
installed at the condenser of the
air conditioner system. The sensor uses an electrostatic volume
pressure transducer to convert refrigerant pressure to voltage. The
voltage signal is sent to ECM, and ECM controls cooling fan system.
Diagnosis ProcedureINFOID:0000000003771730
1.CHECK REFRIGERANT PRESSURE SENSOR OVERALL FUNCTION
1. Start engine and warm it up to normal operating temperature.
2. Turn A/C switch and blower fan switch ON.
3. Check voltage between ECM terminal 70 and ground with CON- SULT-IIl or tester.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK GROUND CONNECTIONS
1. Turn A/C switch and blower fan switch OFF.
2. Turn ignition switch OFF.
3. Loosen and retighten three ground screws on the body.
BBIA0445E
PBIB2657E
Voltage: 1.0 - 4.0V
PBIB1188E
Revision: December 20092009 QX56

ECM
EC-419
< ECU DIAGNOSIS > [VK56DE]
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ECU DIAGNOSIS
ECM
CONSULT-lll Reference Valu
e in Data Monitor ModeINFOID:0000000003771731
Remarks:
z Specification data are reference values.
z Specification data are output/input values which are detected or supplied by the ECM at the connector.
* Specification data may not be directly relat ed to their components signals/values/operations.
i.e. Adjust ignition timing with a timi ng light before monitoring IGN TIMING, because the monitor may show the specification data in spite of the
ignition timing not being adjusted to the s pecification data. This IGN TIMING monitors the data calculated by the ECM according to the signals
input from the camshaft position sensor an d other ignition timing related sensors.
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEED  Run engine and compare CONSULT-IIl value with the tachometer indica-
tion. Almost the same speed as the
tachometer indication.
MAS A/F SE-B1 See EC-74
.
B/FUEL SCHDL See EC-74
.
A/F ALPHA-B1
A/F ALPHA-B2 See
EC-74
.
COOLAN TEMP/S  Engine: After warming up More than 70 °C (158 °F)
A/F SEN1 (B1)
A/F SEN1 (B2)  Engine: After warming up Maintaining engine speed at 2,000 rpm Fluctuates around 2.2 V
HO2S2 (B1)
HO2S2 (B2)  Revving engine from idle to 3,000 rpm quickly after the following conditions
are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load 0 - 0.3V
←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2)  Revving engine from idle to 3,000 rpm quickly after the following conditions
are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1 minute under no load LEAN
←→ RICH
VHCL SPEED SE  Turn drive wheels and compare CONSULT-IIl value with the speedometer
indication. Almost the same speed as the
speedometer indication
BATTERY VOLT  Ignition switch: ON (Engine stopped) 11 - 14V
ACCEL SEN 1 Ignition switch: ON
(Engine stopped) Accelerator pedal: Fully released 0.5 - 1.0V
Accelerator pedal: Fully depressed 4.2 - 4.8V
ACCEL SEN 2*
1Ignition switch: ON (Engine stopped) Accelerator pedal: Fully released 0.5 - 1.0V
Accelerator pedal: Fully depressed 4.2 - 4.8V
TP SEN 1-B1
TP SEN 2-B1 Ignition switch: ON
(Engine stopped)
 Selector lever: D Accelerator pedal: Fully released More than 0.36V
Accelerator pedal: Fully depressed Less than 4.75V
EVAP SYS PRES  Ignition switch: ON Approx. 1.8 - 4.8V
START SIGNAL  Ignition switch: ON → START → ON OFF → ON → OFF
CLSD THL POS Ignition switch: ON
(Engine stopped) Accelerator pedal: Fully released ON
Accelerator pedal: Slightly depressed OFF
AIR COND SIG  Engine: After warming up, idle the
engine Air conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)
ON
P/N POSI SW  Ignition switch: ON Selector lever: P or N ON
Selector lever: Except above OFF
PW/ST SIGNAL  Engine: After warming up, idle the
engine Steering wheel: Not being turned
(Forward direction)
OFF
Steering wheel: Being turned ON
Revision: December 20092009 QX56

EC-420
< ECU DIAGNOSIS >[VK56DE]
ECM
LOAD SIGNAL  Ignition switch: ONRear window defogger switch is ON
and/or lighting switch is in 2nd.
ON
Rear window defogger switch is OFF
and lighting switch is OFF. OFF
IGNITION SW  Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW  Engine: After warming up, idle the
engine Heater fan control switch: ON ON
Heater fan control switch: OFF OFF
BRAKE SW  Ignition switch: ON Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
INJ PULSE-B1
INJ PULSE-B2  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle 2.0 - 2.8 msec
2,000 rpm 1.9 - 2.9 msec
IGN TIMING  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle 10
° - 20 ° BTDC
2,000 rpm 25 ° - 45 ° BTDC
CAL/LD VALUE  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle 14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle 3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
PURG VOL C/V  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle
(Accelerator pedal: Not depressed
even slightly, after engine starting.)
0%
2,000 rpm —
INT/V TIM (B1)
INT/V TIM (B2)  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle
−5 ° - 5 °CA
2,000 rpm Approx. 0 ° - 20 °CA
INT/V SOL (B1)
INT/V SOL (B2)  Engine: After warming up
 Selector lever: P or N
 Air conditioner switch: OFF
No load Idle 0% - 2%
2,000 rpm Approx. 25% - 50%
AIR COND RLY  Engine: After warming up, idle the
engine Air conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor: Operates)
ON
FUEL PUMP RLY
 For 1 second after turning ignition switch ON
 Engine running or cranking ON
 Except above conditions OFF
VENT CONT/V  Ignition switch: ON OFF
THRTL RELAY  Ignition switch: ON ON
COOLING FAN  Engine: After warming up, idle the
engine
 Air conditioner switch: OFF Engine coolant temperature: 99
°C
(210 °F) or less OFF
Engine coolant temperature: 100 °C
(212 °F) or more HI
HO2S2 HTR (B1)
HO2S2 HTR (B2)  Engine speed: Below 3,600 rpm after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load ON
 Engine speed: Above 3,600 rpm OFF
MONITOR ITEM CONDITION SPECIFICATION
Revision: December 20092009 QX56