2009 INFINITI QX56 steering

EC-5
C
DE
F
G H
I
J
K L
M
EC A
N
O P
On Board Diagnosis Logic ..................................
..
295
P1211 TCS CONTROL UNIT ...........................296
Description .......................................................... ..296
On Board Diagnosis Logic ....................................296
DTC Confirmation Procedure ................................296
Diagnosis Procedure .............................................296
P1212 TCS COMMUNICATION LINE ..............297
Description .......................................................... ..297
On Board Diagnosis Logic ....................................297
DTC Confirmation Procedure ................................297
Diagnosis Procedure .............................................297
P1217 ENGINE OVER TEMPERATURE .........298
On Board Diagnosis Logic .................................. ..298
Overall Function Check .........................................298
Diagnosis Procedure .............................................299
Main 13 Causes of Overheating ............................300
P1225 TP SENSOR ..........................................302
Component Description ....................................... ..302
On Board Diagnosis Logic ....................................302
DTC Confirmation Procedure ................................302
Diagnosis Procedure .............................................302
P1226 TP SENSOR ..........................................304
Component Description ....................................... ..304
On Board Diagnosis Logic ....................................304
DTC Confirmation Procedure ................................304
Diagnosis Procedure .............................................304
P1421 COLD START CONTROL .....................306
Description .......................................................... ..306
On Board Diagnosis Logic ....................................306
DTC Confirmation Procedure ................................306
Diagnosis Procedure .............................................306
P1550 BATTERY CURRENT SENSOR ...........308
Component Description ....................................... ..308
On Board Diagnosis Logic ....................................308
DTC Confirmation Procedure ................................308
Diagnosis Procedure .............................................308
Component Inspection ..........................................310
P1551, P1552 BATTERY CURRENT SEN-
SOR ..................................................................
312
Component Description ....................................... ..312
On Board Diagnosis Logic ....................................312
DTC Confirmation Procedure ................................312
Diagnosis Procedure .............................................312
Component Inspection ..........................................314
P1553 BATTERY CURRENT SENSOR ...........316
Component Description ....................................... ..316
On Board Diagnosis Logic ....................................316
DTC Confirmation Procedure ................................316
Diagnosis Procedure .............................................316
Component Inspection ..........................................318
P1554 BATTERY CURRENT SENSOR ...........320
Component Description ....................................... ..320
On Board Diagnosis Logic .....................................320
Overall Function Check .........................................320
Diagnosis Procedure .............................................321
Component Inspection ...........................................322
P1564 ICC STEERING SWITCH .....................324
Component Description .........................................324
On Board Diagnosis Logic .....................................324
DTC Confirmation Procedure ................................324
Diagnosis Procedure .............................................324
Component Inspection ...........................................326
P1564 ASCD STEERING SWITCH .................328
Component Description .........................................328
On Board Diagnosis Logic .....................................328
DTC Confirmation Procedure ................................328
Diagnosis Procedure .............................................328
Component Inspection ...........................................330
P1568 ICC FUNCTION ....................................332
On Board Diagnosis Logic .....................................332
DTC Confirmation Procedure ................................332
Diagnosis Procedure .............................................332
P1572 ICC BRAKE SWITCH ..........................333
Component Description .........................................333
On Board Diagnosis Logic .....................................333
DTC Confirmation Procedure ................................333
Diagnosis Procedure .............................................334
Component Inspection ...........................................337
P1572 ASCD BRAKE SWITCH ......................339
Component Description .........................................339
On Board Diagnosis Logic .....................................339
DTC Confirmation Procedure ................................339
Diagnosis Procedure .............................................340
Component Inspection ...........................................343
P1574 ICC VEHICLE SPEED SENSOR .........344
Component Description .........................................344
On Board Diagnosis Logic .....................................344
DTC Confirmation Procedure ................................344
Diagnosis Procedure .............................................344
P1574 ASCD VEHICLE SPEED SENSOR .....346
Component Description .........................................346
On Board Diagnosis Logic .....................................346
DTC Confirmation Procedure ................................346
Diagnosis Procedure .............................................346
P1805 BRAKE SWITCH .................................348
Description .............................................................348
On Board Diagnosis Logic .....................................348
DTC Confirmation Procedure ................................348
Diagnosis Procedure .............................................348
Component Inspection ...........................................350
P2100, P2103 THROTTLE CONTROL MO-
TOR RELAY ....................................................
351
Component Description .........................................351
Revision: December 20092009 QX56

INSPECTION AND ADJUSTMENTEC-13
< BASIC INSPECTION > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
INSPECTION AND ADJUSTMENT
Basic InspectionINFOID:0000000003771294
1.INSPECTION START
1. Check service records for any recent repairs that ma y indicate a related malfunction, or a current need for
scheduled maintenance.
2. Open engine hood and check the following:
- Harness connectors for improper connections
- Wiring harness for improper connections, pinches and cut
- Vacuum hoses for splits, kinks and improper connections
- Hoses and ducts for leaks
- Air cleaner clogging
- Gasket
3. Confirm that electrical or mechanical loads are not applied.
- Headlamp switch is OFF.
- Air conditioner switch is OFF.
- Rear window defogger switch is OFF.
- Steering wheel is in the straight-ahead position, etc.
4. Start engine and warm it up until engine coolant temperature indicator points the middle of gauge.
Ensure engine stays below 1,000 rpm.
5. Run engine at about 2,000 rpm for about 2 minutes under no load.
6. Make sure that no DTC is displayed with CONSULT-III or GST.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.REPAIR OR REPLACE
Repair or replace components as necessary according to corresponding Diagnostic Procedure.
>> GO TO 3.
3.CHECK TARGET IDLE SPEED
With CONSULT-III
1. Run engine at about 2,000 rpm for about 2 minutes under no load.
SEF983U
SEF976U
SEF977U
Revision: December 20092009 QX56

EC-18
< BASIC INSPECTION >[VK56DE]
INSPECTION AND ADJUSTMENT
With CONSULT-III
1. Check the VIN of the vehicle and note it. Refer to
GI-20, "Model Variation".
2. Turn ignition switch ON and engine stopped.
3. Select “VIN REGISTRATION ” in “WORK SUPPORT” mode.
4. Follow the instruction of CONSULT-III display.
Accelerator Pedal Released Position LearningINFOID:0000000003771298
DESCRIPTION
Accelerator Pedal Released Position Learning is an operati on to learn the fully released position of the accel-
erator pedal by monitoring the accelerator pedal positi on sensor output signal. It must be performed each time
harness connector of accelerator pedal pos ition sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.
Throttle Valve Closed Position LearningINFOID:0000000003771299
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to l earn the fully closed position of the throttle valve by
monitoring the throttle position sensor output signal . It must be performed each time harness connector of
electric throttle control actuator or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF wait at least 10 seconds. Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.
Idle Air Volume LearningINFOID:0000000003771300
DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range. It must be performed under any of the following conditions:
 Each time electric throttle control actuator or ECM is replaced.
 Idle speed or ignition timing is out of specification.
PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.
 Battery voltage: More than 12.9V (At idle)
 Engine coolant temperature: 70 - 100 °C (158 - 212 °F)
 Select lever: P or N
 Electric load switch: OFF (Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine is
start the headlamp will not be illuminated.
 Steering wheel: Neutral (Straight-ahead position)
 Vehicle speed: Stopped
 Transmission: Warmed-up
- With CONSULT-III: Drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/T” system indi-
cates less than 0.9V.
- Without CONSULT-III: Drive vehicle for 10 minutes.
OPERATION PROCEDURE
Revision: December 20092009 QX56

EC-22
< FUNCTION DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM
Engine Control Comp onent Parts Location
INFOID:0000000003771302
1. ECM 2. Battery current sensor 3. Power steering pressure sensor
4. Ignition coil (with power transistor)
and spark plug (bank 2) 5. Refrigerant pressure sensor 6. Intake valve timing control position
sensor (bank 2)
7. Intake valve timing control solenoid valve (bank 2) 8. Engine coolant temperature sensor 9. Electric throttle control actuator
10. Intake valve timing control position sensor (bank 1) 11. Intake valve timing control solenoid
valve (bank 1) 12. Cooling fan motor
13. Camshaft position sensor (PHASE) 14. I gnition coil (with power transistor)
and spark plug (bank 1) 15. Mass air flow sensor (with intake air
temperature sensor)
16. A/F sensor 1 (bank 1) 17. EVAP service port 18. Fuel injector (bank 1)
19. Knock sensor (bank 1) 20. EVAP canister purge volume control solenoid valve21. Knock sensor (bank 2)
22. Fuel injector (bank 2) 23. A/F sensor 1 (bank 2) 24. IPDM E/R
BBIA0743E
Revision: December 20092009 QX56

EC-26
< FUNCTION DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM
1. Knock sensor (bank 1) (view with en-
gine removed) 2. Knock sensor (bank 2) (view with en-
gine removed) 3. Battery current sensor
4. Power steering pressure sensor 5. Power steering fluid reservoir 6. Intake manifold
7. Engine coolant temperature sensor 8. Ignition coils (with power transistor) 9. Ignition coil (with power transistor)
10. Injector harness connectors (bank 2) 11. Injector harness connectors (bank 1) : Vehicle front
BBIA0384E
Revision: December 20092009 QX56

EC-28
< FUNCTION DIAGNOSIS >[VK56DE]
MULTIPORT FUEL INJECTION SYSTEM
MULTIPORT FUEL INJECTION SYSTEM
System DescriptionINFOID:0000000003771303
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is
determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
VARIOUS FUEL INJECTION I NCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compens ated to improve engine performance under various operat-
ing conditions as listed below.
 During warm-up
 When starting the engine
 During acceleration
 Hot-engine operation
 When selector lever is changed from N to D
 High-load, high-speed operation

 During deceleration
 During high engine speed operation
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
TCM Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) VDC/TCS operation command*
2
Air conditioner switchAir conditioner operation*2
Wheel sensorVehicle speed*2
Revision: December 20092009 QX56

EC-32
< FUNCTION DIAGNOSIS >[VK56DE]
AIR CONDITIONING CUT CONTROL
AIR CONDITIONING CUT CONTROL
Input/Output Signal ChartINFOID:0000000003771305
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
System DescriptionINFOID:0000000003771306
This system improves engine operati
on when the air conditioner is used.
Under the following conditions, the air conditioner is turned OFF.
 When the accelerator pedal is fully depressed.
 When cranking the engine.
 At high engine speeds.
 When the engine coolant temperature becomes excessively high.
 When operating power steering during low engine speed or low vehicle speed.
 When engine speed is excessively low.
 When refrigerant pressure is excessively low or high.
Sensor Input Signal to ECM ECM function Actuator
Air conditioner switch Air conditioner ON signal*
1
Air conditioner
cut controlAir conditio
ner relay
Accelerator pedal position sensor Accelerator pedal position
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)
Engine speed*
2
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
Wheel sensor
Vehicle speed*
1
Revision: December 20092009 QX56

AUTOMATIC SPEED CONTROL DEVICE (ASCD)EC-33
< FUNCTION DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System DescriptionINFOID:0000000003771307
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a dr
iver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/
h (25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric thro ttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE i ndicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
NOTE:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.
SET OPERATION
Press MAIN switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press SET/COAST switch. (Then SET indi cator in combination meter illuminates.)
ACCELERATE OPERATION
If the RESUME/ACCELERATE switch is pressed during cruise control driving, increase the vehicle speed until
the switch is released or vehicle speed reac hes maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.
 CANCEL switch is pressed
 More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)
 Brake pedal is depressed
 Selector lever is changed to N, P, R position
 Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
 VDC system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.
 Engine coolant temperature is slightly higher than t he normal operating temperature, CRUISE indicator may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE indicator will
stop blinking and the cruise operation will be able to work by pressing SET/COAST switch or RESUME/
ACCELERATE switch.
 Malfunction for some self-diagnoses regarding ASCD control: SET indicator will blink quickly.
If MAIN switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled and vehicle
speed memory will be erased.
COAST OPERATION
When the SET/COAST switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
RESUME OPERATION
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator
Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Wheel sensor Vehicle speed*
TCM
Gear position
Powertrain revolution*
Revision: December 20092009 QX56