INFINITI QX56 2009 Factory Service Manual

EC-414
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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

POSITIVE CRANKCASE VENTILATIONEC-415
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1. Check hoses and hose connections for leaks.
2. Disconnect all hoses and clean with compressed air. If any hose
cannot be freed of obstructions, replace.
S-ET277
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

REFRIGERANT PRESSURE SENSOREC-417
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Refer to
EC-85, "Ground Inspection".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace ground connections.
3.CHECK REFRIGERANT PRESSURE SE NSOR POWER SUPPLY CIRCUIT
1. Disconnect refrigerant pressu re sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between refrigerant pressure sensor terminal 1 and ground with CONSULT-IIl or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E5, F14
 Harness for open or short between ECM and refrigerant pressure sensor
>> Repair harness or connectors.
5.CHECK REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between refrigerant pressure sensor terminal 3 and ECM terminal 67. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0354E
BBIA0445E
Voltage: Approximately 5V
PBIB0188E
Continuity should exist.
Revision: December 20092009 QX56

EC-418
< COMPONENT DIAGNOSIS >[VK56DE]
REFRIGERANT PRESSURE SENSOR
6.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E5, F14
 Harness for open or short between ECM and refrigerant pressure sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK REFRIGERANT PRESSURE SENSOR INPU T SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 70 and refrigerant pressure sensor terminal 2. Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> GO TO 8.
8.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E5, F14
 Harness for open or short between ECM and refrigerant pressure sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
9.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
OK or NG
OK >> Replace refrigerant pressure sensor.
NG >> Repair or replace. Continuity should exist.
Revision: December 20092009 QX56

ECM
EC-419
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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

ECM
EC-421
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*1: Accelerator pedal position sensor 2 signal and throttle position sensor 2 signal are converted by ECM internally. Thus, the
y differ
from ECM terminals voltage signal.
*2: Before measuring the terminal voltage, confirm the battery is fully charged. Refer to PG-77
.
I/P PULLY SPD  Vehicle speed: More than 20 km/h (12 MPH)
Almost the same speed as the
tachometer indication
VEHICLE SPEED  Turn drive wheels and compare CONSULT-IIl value with the speedometer
indication. Almost the same speed as the
speedometer indication
TRVL AFTER MIL  Ignition switch: ON Vehicle has traveled after MIL has
turned ON.0 - 65,535 km
(0 - 40,7
23 mile)
A/F S1 HTR (B1)
A/F S1 HTR (B2)  Engine: After warming up, idle the engine 4 - 100%
AC PRESS SEN Engine: Idle
 Both A/C switch and blower fan switch: ON (Compressor operates.)
1.0 - 4.0V
VHCL SPEED SE  Turn drive wheels and compare CONSULT-IIl value with the speedometer
indication. Almost the same speed as the
speedometer indication
SET VHCL SPD  Engine: Running ASCD: Operating. The preset vehicle speed is dis-
played.
MAIN SW  Ignition switch: ON MAIN switch: Pressed ON
MAIN switch: Released OFF
CANCEL SW  Ignition switch: ON CANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW  Ignition switch: ON RESUME/ACCELERATE switch:
Pressed
ON
RESUME/ACCELERATE switch: Re-
leased OFF
SET SW  Ignition switch: ON SET/COAST switch: Pressed ON
SET/COAST switch: Released OFF
DIST SW  Ignition switch: ON DISTANCE switch: Pressed ON
DISTANCE switch: Released OFF
BRAKE SW1  Ignition switch: ON Brake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2  Ignition switch: ON Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
CRUISE LAMP  Ignition switch: ON MAIN switch: Pressed at the 1st time
→
at the 2nd time ON
→ OFF
SET LAMP  MAIN switch: ON
 Vehicle speed: Between 40 km/h
(25 MPH) and 144 km/h (89
MPH) ASCD: Operating ON
ASCD: Not operating OFF
ALT DUTY  Engine: Idle 0 - 80%
BAT CUR SEN  Engine speed: Idle
 Battery: Fully charged*
2
 Selector lever: P or N
 Air conditioner switch: OFF
 No load Approx. 2,600 - 3,500mV
ALT DUTY SIG  Power generation voltage variable control: Operating ON
 Power generation voltage variable control: Not operating OFF
MONITOR ITEM CONDITION SPECIFICATION
Revision: December 20092009 QX56

EC-422
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ECM
ECM Harness Connector Terminal Layout
INFOID:0000000003771732
ECM Terminal and Reference ValueINFOID:0000000003771733
PREPARATION
ECM is located in the engine room passenger side behind battery.
ECM INSPECTION TABLE
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-IIl.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground ot her than ECM terminals, such as the ground.
PBIB3368E
BBIA0386E
TER-
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NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
1 B ECM ground [Engine is running]
 Idle speedBody ground
2 LG/B A/F sensor 1 heater (bank 1) [Engine is running]

Warm-up condition
 Idle speed (More than 140 seconds after starting en-
gine) Approximately 2.9 - 8.8V
3L Throttle contro
l motor relay
power supply [Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor (Close) [Ignition switch: ON]
 Engine: Stopped
 Selector lever: D
 Accelerator pedal: Fully released0 - 14V
PBIA8148J
PBIB1104E
Revision: December 20092009 QX56

ECM
EC-423
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5 L/B Throttle control motor (Open)
[Ignition switch: ON]
 Engine: Stopped
 Selector lever: D
 Accelerator pedal: Fully depressed0 - 14V
6GR Heated oxygen sensor 2 heat-
er (bank 1) [Engine is running]
 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 0 - 1.0V
[Ignition switch: ON]
 Engine: Stopped
[Engine is running]
 Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
10 W Intake valve timing control so-
lenoid valve (bank 1) [Engine is running]

Warm-up condition
 Idle speed BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000rpm 7 - 12V
11 L G Intake valve timing control so-
lenoid valve (bank 2) [Engine is running]

Warm-up condition
 Idle speed BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000rpm 7 - 12V
12 R Power steering pressure sen-
sor [Engine is running]
 Steering wheel: Being turned
0.5 - 4.5V
[Engine is running]
 Steering wheel: Not being turned 0.4 - 0.8V
TER-
MI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
PBIB1105E
PBIB1790E
PBIB1790E
Revision: December 20092009 QX56