power steering INFINITI QX56 2009 Factory Manual PDF

P0643 SENSOR POWER SUPPLYEC-285
< COMPONENT DIAGNOSIS > [VK56DE]
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P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000003771567
This self-diagnosis has the on
e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771568
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-285, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771569
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643 Sensor power supply circuit
short ECM detects a voltage of power source
for sensor is excessively low or high.  Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Battery current sensor circuit is shorted.)
(Refrigerant pressure se nsor circuit is short-
ed.)
(EVAP control system pressure sensor circuit
is shorted.)
 Accelerator pedal position sensor
 Power steering pressure sensor
 Refrigerant pressure sensor
 EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
BBIA0354E
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EC-286
< COMPONENT DIAGNOSIS >[VK56DE]
P0643 SENSOR POWER SUPPLY
NG >> Repair or replace ground connections.
2.CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUITS
Check harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4.CHECK COMPONENTS
Check the following.
 EVAP control system pressure sensor (Refer to EC-244, "Component Inspection"
.)
 Power steering pressure sensor (Refer to EC-279, "Component Inspection"
.)
 Battery current sensor (Refer to EC-310, "Component Inspection"
.)
 Refrigerant pressure sensor
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5.CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-376, "Component Inspection"
.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
JMBIA0601ZZ
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3
EC-432, "Wiring Diagram - ENGINE
CONTROL SYSTEM -"
49Refrigerant pressure sensor terminal 1
Battery current sensor terminal 1
68 Power steering pressure sensor terminal 1
90 APP sensor terminal 7
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EC-326
< COMPONENT DIAGNOSIS >[VK56DE]
P1564 ICC STEERING SWITCH
OK >> GO TO 8.
NG >> GO TO 3.
3.CHECK ICC STEERING SWITCH GRO
UND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect combination switch harness connector.
4. Check harness continuity between combination switch terminal 15 and ECM terminal 67. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors M31, E152
 Harness connectors E5, F14
 Combination switch (spiral cable)
 Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK ICC STEERING SWITCH INPUT S IGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 99 and combination switch terminal 14. Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors M31, E152
 Combination switch (spiral cable)
 Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK ICC STEERING SWITCH
Refer to EC-326, "Component Inspection"
.
OK or NG
OK >> GO TO 8.
NG >> Replace ICC steering switch.
8.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000003771629
ICC STEERING SWITCH
Continuity should exist.
Continuity should exist.
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EC-330
< COMPONENT DIAGNOSIS >[VK56DE]
P1564 ASCD STEERING SWITCH
2. Disconnect combination switch harness connector M102.
3. Disconnect ECM harness connector.
4. Check harness continuity between combination switch terminal
15 and ECM terminal 67.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors M31, E152
 Harness connectors E5, F14
 Combination switch (spiral cable)
 Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK ASCD STEERING SWITCH INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 99 and combination switch terminal 14. Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors M31, E152
 Combination switch (spiral cable)
 Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK ASCD STEERING SWITCH
Refer to EC-330, "Component Inspection"
.
OK or NG
OK >> GO TO 8.
NG >> Replace ASCD steering switch.
8.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000003771634
ASCD STEERING SWITCH
1. Disconnect combination switch (spiral cable) harness connector M102. Continuity should exist.
BBIA0362E
Continuity should exist.
Revision: December 20092009 QX56

ECM
EC-423
< ECU DIAGNOSIS > [VK56DE]
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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
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ECM
EC-429
< ECU DIAGNOSIS > [VK56DE]
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65
79
80
81
G/R
V/W
W/R
W/G Ignition signal No. 8
Ignition signal No. 6
Ignition signal No. 4
Ignition signal No. 2 [Engine is running]

Warm-up condition
 Idle speed
NOTE:
The pulse cycle changes depending on rpm at
idle 0 - 0.3V
[Engine is running]
 Warm-up condition
 Engine speed: 2,500 rpm 0.1 - 0.6V
82 B/R Sensor ground
(APP sensor 1) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
83 G/W Sensor ground
(APP sensor 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
86 P CAN communication line — —
90 L Sensor power supply
(APP sensor 1) [Ignition switch: ON]
Approximately 5V
91 W/R Sensor power supply
(APP sensor 2) [Ignition switch: ON]
Approximately 5V
94 L CAN communication line — —
98 G/R Accelerator pedal position
sensor 2 [Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully released
0.25 - 0.50V
[Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully depressed 2.0 - 2.5V
99 G/R ASCD steering switch
(Models with ICC system) [Ignition switch: ON]
 ICC steering switch: OFF
Approximately 4.3V
[Ignition switch: ON]
 MAIN switch: Pressed Approximately 0V
[Ignition switch: ON]
 CANCEL switch: Pressed Approximately 1.3V
[Ignition switch: ON]
 RESUME/ACCELERATE switch: Pressed Approximately 3.7V
[Ignition switch: ON]
 SET/COAST switch: Pressed Approximately 3V
[Ignition switch: ON]
 DISTANCE switch: Pressed Approximately 2.2V
TER-
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NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)SEC986C
SEC987C
Revision: December 20092009 QX56

EC-456
< ECU DIAGNOSIS >[VK56DE]
ECM
DTC Index
INFOID:0000000003771737
EMISSION-RELATED DIAGNOSTIC INFORMATION ITEMS
× :Applicable —: Not applicable
2  P0031 P0032 P0051 P0052 Air fuel ratio (A/F) sensor 1 heater
 P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater
 P0075 P0081 Intake valve timing control solenoid valve
 P0130 P0131 P0132 P0133 P0150 P0151 P0152 P0153 P2A00 P2A03 Air fuel ratio (A/F) sensor 1
 P0137 P0138 P0139 P0157 P0158 P0159 Heated oxygen sensor 2
 P0441 EVAP control system purge flow monitoring
 P0443 P0444 P0445 EVAP canister purge volume control solenoid valve
 P0447 P0448 EVAP canister vent control valve
 P0451 P0452 P0453 EVAP control system pressure sensor
 P0550 Power steering pressure sensor
 P0603 ECM power supply
 P0710 P0717 P0720 P0731 P0732 P0733 P0734 P0735 P0740 P0744 P0745 P1730 P1752 P1757 P1762 P1767
P1772 P1774 A/T related sensors, solenoid valves and switches
 P1217 Engine over temperature (OVERHEAT)
 P1140 P1145 Intake valve timing control position sensor
 P1805 Brake switch
 P2100 P2103 P2118 Electric throttle control actuator
 P2101 Electric throttle control function
3  P0011 P0021 Intake valve timing control  P0171 P0172 P0174 P0175 Fuel injection system function
 P0300 - P0308 Misfire
 P0420 P0430 Three way catalyst function
 P0442 EVAP control system (SMALL LEAK)
 P0455 EVAP control system (GROSS LEAK)
 P0456 EVAP control sys tem (VERY SMALL LEAK)
 P0506 P0507 Idle speed control system
 P1148 P1168 Closed loop control
 P1211 TCS control unit
 P1212 TCS communication line
 P1421 Cold start control
 P1564 ICC/ASCD steering switch
 P1568 ICC command value
 P1572 ICC/ASCD brake switch
 P1574 ICC/ASCD vehicle speed sensor
 P2119 Electric throttle control actuator
Priority Detected items (DTC)
Items
(CONSULT-IIl screen terms) DTC*
1
SRT code Trip MIL
Reference
page
CONSULT-IIl
GST*
2ECM*3
CAN COMM CIRCUIT U1000 1000*5—1×EC-86
CAN COMM CIRCUIT U1001
1001*5—1 or 2*9
2*10—
EC-86
CONTROL UNIT(CAN) U1010 1010 — 1 ×EC-284
NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED. P0000 0000
——
Flashing*7EC-55
INT/V TIM CONT-B1 P0011 0011 — 2 ×EC-40
INT/V TIM CONT-B2 P0021 0021 — 2 ×EC-40
A/F SEN1 HTR (B1) P0031 0031 — 2 ×EC-94
A/F SEN1 HTR (B1) P0032 0032 — 2 ×EC-94
HO2S2 HTR (B1) P0037 0037 — 2 ×EC-97
HO2S2 HTR (B1) P0038 0038 — 2 ×EC-97
A/F SEN1 HTR (B2) P0051 0051 — 2 ×EC-94
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EC-476
< SYMPTOM DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM SYMPTOMS
1 - 6: The numbers refer to the order of inspection.
(continued on next page)
SYSTEM — ENGINE MECHANICAL & OTHER
Mass air flow sensor circuit
1
12 2
222 2 EC-103,
EC-109
Engine coolant temperature sensor circuit
333
EC-120,
EC-128
Air fuel ratio (A/F ) sensor 1 circuit EC-136
,
EC-140
,
EC-143
,
EC-146
,
EC-377

Throttle position sensor circuit 22EC-124
,
EC-185
,
EC-302
,
EC-304
,
EC-369
Accelerator pedal position sensor circuit 3 2 1 EC-280
,
EC-362
,
EC-365
,
EC-373
Knock sensor circuit 2 3 EC-195
Crankshaft position sensor (POS) circuit 2 2EC-198
Camshaft position sensor (PHASE) circuit 3 2 EC-202
Vehicle speed signal circuit 2 3 3 3 EC-271
Power steering pressure sensor circuit 2 3 3 EC-277
ECM 22333333333 EC-280,
EC-282
Intake valve timing control solenoid valve cir-
cuit 32 13223 3
EC-100
Transmission range signal circuit 3 3 3 3 3 EC-288
Refrigerant pressure sensor circuit 2 3 3 4EC-416
Electrical load signal circuit 3EC-390
Air conditioner circuit 223333333 3 2HAC-25
ABS actuator and electric unit (control unit) 4 BRC-37
SYMPTOM
Refer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
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PRECAUTIONSEM-3
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental
Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005885848
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers, always switch the Ignition OFF, disconnect the battery, and wait at least 3 minutes before performing any service.
Precaution Necessary for Steering Wheel Rotation After Battery Disconnect
INFOID:0000000005885849
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NATS (NISSAN ANTI-THEFT SYS-
TEM).
• Remove and install all control units after disconnecti ng both battery cables with the ignition knob in the
″ LOCK ″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NATS , an electrically controlled steering lock mech-
anism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery power is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC ″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be
rotated.
4. Perform the necessary repair operation.
Revision: December 20092009 QX56

EM-4
< PRECAUTION >
PRECAUTIONS
5. When the repair work is completed, return the ignition switch to the ″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of a ll control units using CONSULT-III.
Precaution for Drain Engine CoolantINFOID:0000000005885850
Drain engine coolant when engine is cooled.
Precaution for Disconnecting Fuel PipingINFOID:0000000005885851
• Before starting work, make sure no fire or spark producing items are in the work area.
• Release fuel pressure before disconnecting and disassembly.
• After disconnecting pipes, plug openings to stop fuel leakage.
Precaution for Removal and DisassemblyINFOID:0000000005885852
• When instructed to use special service tools, use the s pecified tools. Always be careful to work safely, avoid
forceful or uninstructed operations.
• Exercise maximum care to avoid damage to mating or sliding surfaces.
• Cover openings of engine system with tape or the equivalent, if necessary, to seal out foreign materials.
• Mark and arrange disassembly parts in an organi zed way for easy troubleshooting and assembly.
• When loosening nuts and bolts, as a basic rule, start with the one furthest outside, then the one diagonally opposite, and so on. If the order of loosening is specified, do exactly as specified. Power tools may be used
where noted in the step.
Precaution for Inspection, Repair and ReplacementINFOID:0000000005885853
Before repairing or replacing, thoroughly inspect parts. Inspect new replacement parts in the same way, and
replace if necessary.
Precaution for Assembly and InstallationINFOID:0000000005885854
• Use torque wrench to tighten bolts or nuts to specification.
• When tightening nuts and bolts, as a basic rule, equally tighten in several different steps starting with theones in center, then ones on inside and outside diagonally in this order. If the order of tightening is specified,
do exactly as specified.
• Replace with new gasket, packing, oil seal or O-ring.
• Thoroughly wash, clean, and air-blow each part. Carefully check engine oil or engine coolant passages for any restriction and blockage.
• Avoid damaging sliding or mating surfaces. Completely remove foreign materials such as cloth lint or dust. Before assembly, oil sliding surfaces well.
• Release air within route when refilling after draining engine coolant.
• Before starting engine, apply fuel pressure to fuel lines with turning ignition switch ON (with engine stopped). Then make sure that there are no leaks at fuel line connections.
• After repairing, start engine and increase engine s peed to check engine coolant, fuel, oil, and exhaust sys-
tems for leakage.
Parts Requiring Angular TighteningINFOID:0000000005885855
• For final tightening of the following engine parts use Tool:
- Cylinder head bolts
- Main bearing cap bolts
- Connecting rod cap bolts
- Crankshaft pulley bolt (No angle wrench is required as the bolt flange is provided with notches for angle tightening)
• Do not use a torque value for final tightening.
• The torque value for these parts are for a preliminary step.
• Ensure thread and seat surfaces are clean and lightly coated with engine oil. Tool number : KV10112100 (BT-8653-A)
Revision: December 20092009 QX56