relay INFINITI QX56 2011 Factory Service Manual
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EC-6
DTC Logic ..............................................................364
Diagnosis Procedure  .............................................365
P0527 COOLING FAN SPEED SENSOR  .......367
DTC Logic ............................................................ ..367
Diagnosis Procedure  .............................................367
Component Inspection (Cooling Fan Speed Sen-
sor) ........................................................................
369
P0550 PSP SENSOR .......................................371
DTC Logic ............................................................ ..371
Diagnosis Procedure  .............................................371
Component Inspection (Power Steering Pressure 
Sensor) ..................................................................
373
P0603 ECM POWER SUPPLY  ........................374
DTC Logic ............................................................ ..374
Diagnosis Procedure  .............................................374
P0605 ECM  ......................................................376
DTC Logic ............................................................ ..376
Diagnosis Procedure  .............................................376
P0607 ECM  ......................................................378
DTC Logic ............................................................ ..378
Diagnosis Procedure  .............................................378
P0611 ECM PROTECTION  .............................379
Description ........................................................... ..379
DTC Logic ..............................................................379
Diagnosis Procedure  .............................................379
P062B ECM  .....................................................380
Description ........................................................... ..380
DTC Logic ..............................................................380
Diagnosis Procedure  .............................................380
P0643 SENSOR POWER SUPPLY  .................381
DTC Logic ............................................................ ..381
Diagnosis Procedure  .............................................381
P0850 PNP SWITCH  .......................................383
Description ........................................................... ..383
DTC Logic ..............................................................383
Component Function Check  ..................................384
Diagnosis Procedure  .............................................384
P1087, P1088 VVEL SYSTEM  ........................386
DTC Logic ............................................................ ..386
Diagnosis Procedure  .............................................386
P1089, P1092 VVEL CONTROL SHAFT PO-
SITION SENSOR  .............................................
387
DTC Logic ............................................................ ..387
Diagnosis Procedure  .............................................387
P1090, P1093 VVEL ACTUATOR MOTOR .....390
DTC Logic ............................................................ ..390
Diagnosis Procedure  .............................................390
Component Inspection (VVEL ACTUATOR MO-
TOR ASSEMBLY)  .................................................
392
Component Inspection  (VVEL ACTUATOR 
HOUSING ASSEMBLY) ......... ...............................
392
P1091 VVEL ACTUATOR MOTOR RELAY ... ..393
DTC Logic  ............................................................ .393
Diagnosis Procedure .............................................393
Component Inspection (VVEL Actuator Motor Re-
lay) ....................................................................... .
395
P1148, P1168 CLOSED LOOP CONTROL  .....396
DTC Logic  ............................................................ .396
Diagnosis Procedure .............................................396
P1197 OUT OF GAS  ........................................397
Description ........................................................... .397
DTC Logic  .............................................................397
Diagnosis Procedure .............................................398
P1212 TCS COMMUNICATION LINE  ..............399
Description ........................................................... .399
DTC Logic  .............................................................399
Diagnosis Procedure .............................................399
P1217 ENGINE OVER TEMPERATURE  .........400
DTC Logic  ............................................................ .400
Component Function Check  .................................400
Diagnosis Procedure .............................................401
P1220 FUEL PUMP CONTROL MODULE 
(FPCM) ..............................................................
403
DTC Logic  ............................................................ .403
Diagnosis Procedure .............................................403
Component Inspection (FPCM)  ............................405
P1225 TP SENSOR  ..........................................406
DTC Logic  ............................................................ .406
Diagnosis Procedure .............................................406
P1226 TP SENSOR  ..........................................407
DTC Logic  ............................................................ .407
Diagnosis Procedure .............................................407
P1421 COLD START CONTROL  .....................408
Description ........................................................... .408
DTC Logic  .............................................................408
Diagnosis Procedure .............................................408
P1423, P1424 COLD START CONTROL  ........410
Description ........................................................... .410
DTC Logic  .............................................................410
Diagnosis Procedure .............................................410
P1550 BATTERY CURRENT SENSOR  ...........412
DTC Logic  ............................................................ .412
Diagnosis Procedure .............................................412
Component Inspection (Battery Current Sensor)  ..414
P1551, P1552 BATTERY CURRENT SEN-
SOR ..................................................................
416
DTC Logic  ............................................................ .416
Diagnosis Procedure .............................................416
Component Inspection (Battery Current Sensor)  ..419
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EC-7
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P1553 BATTERY CURRENT SENSOR  ......... ..420
DTC Logic  ........................................................... ..420
Diagnosis Procedure  .............................................420
Component Inspection (Battery Current Sensor) ..423
P1554 BATTERY CURRENT SENSOR  ...........424
DTC Logic  ........................................................... ..424
Component Function Check ..................................424
Diagnosis Procedure  .............................................425
Component Inspection (Battery Current Sensor) ..427
P1556, P1557 BATTERY TEMPERATURE 
SENSOR ...........................................................
428
DTC Logic  ........................................................... ..428
Diagnosis Procedure  .............................................428
Component Inspection (Battery Temprature Sen-
sor) ........................................................................
430
P1564 ASCD STEERING SWITCH  ..................431
DTC Logic  ........................................................... ..431
Diagnosis Procedure  .............................................431
Component Inspection (ASCD Steering Switch)  ...433
P1564 ICC STEERING SWITCH  ......................434
DTC Logic  ........................................................... ..434
Diagnosis Procedure  .............................................434
Component Inspection (ICC Steering Switch) .......436
P1568 ICC FUNCTION  .....................................437
DTC Logic  ........................................................... ..437
Diagnosis Procedure  .............................................437
P1572 ASCD BRAKE SWITCH  .......................438
DTC Logic  ........................................................... ..438
Diagnosis Procedure  .............................................439
Component Inspection (ASCD Brake Switch)  .......442
Component Inspection (Stop Lamp Switch)  ..........442
P1572 ICC BRAKE SWITCH  ...........................443
DTC Logic  ........................................................... ..443
Diagnosis Procedure  .............................................444
Component Inspection (ICC Brake Switch) ...........445
Component Inspection (Stop Lamp Switch)  ..........446
P1574 ASCD VEHICLE SPEED SENSOR  ......447
Description .......................................................... ..447
DTC Logic  .............................................................447
Diagnosis Procedure  .............................................447
P1574 ICC VEHICLE SPEED SENSOR  ..........449
Description .......................................................... ..449
DTC Logic  .............................................................449
Diagnosis Procedure  .............................................449
P1606 VVEL CONTROL MODULE  ..................451
DTC Logic  ........................................................... ..451
Diagnosis Procedure  .............................................451
P1607 VVEL CONTROL MODULE  ..................452
DTC Logic  ........................................................... ..452
Diagnosis Procedure  .............................................452
P1608 VVEL SENSOR POWER SUPPLY  ......453
DTC Logic ............................................................ ..453
Diagnosis Procedure  .............................................453
P1805 BRAKE SWITCH  .................................455
DTC Logic ..............................................................455
Diagnosis Procedure  .............................................455
Component Inspection (Stop Lamp Switch)  ..........456
P2100, P2103 THROTTLE CONTROL MO-
TOR RELAY  ....................................................
458
DTC Logic ..............................................................458
Diagnosis Procedure  .............................................458
P2101 ELECTRIC THROTTLE CONTROL 
FUNCTION ......................................................
460
Description ........................................................... ..460
DTC Logic ..............................................................460
Diagnosis Procedure  .............................................460
Component Inspection ...........................................462
Special Repair Requirement ..................................463
P2118 THROTTLE CONTROL MOTOR  .........464
DTC Logic ..............................................................464
Diagnosis Procedure  .............................................464
Component Inspection (Electric Throttle Control 
Motor) ....................................................................
465
P2119 ELECTRIC THROTTLE CONTROL 
ACTUATOR .....................................................
466
DTC Logic ..............................................................466
Diagnosis Procedure  .............................................466
P2122, P2123 APP SENSOR  .........................468
DTC Logic ..............................................................468
Diagnosis Procedure  .............................................468
Component Inspection (Accelerator Pedal Posi-
tion Sensor)  ...........................................................
470
P2127, P2128 APP SENSOR  .........................471
DTC Logic ..............................................................471
Diagnosis Procedure  .............................................471
Component Inspection (Accelerator Pedal Posi-
tion Sensor)  ...........................................................
474
P2135 TP SENSOR .........................................475
DTC Logic ..............................................................475
Diagnosis Procedure  .............................................475
Component Inspection (Throttle Position Sensor) ..476
P2138 APP SENSOR  ......................................478
DTC Logic ..............................................................478
Diagnosis Procedure  .............................................478
Component Inspection (Accelerator Pedal Posi-
tion Sensor)  ...........................................................
481
P2539, P2541, P2542 LOW FUEL PRES-
SURE SENSOR ...............................................
483
DTC Logic ..............................................................483
Diagnosis Procedure  .............................................483
Component Inspection ...........................................485
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COMPONENT PARTSEC-19
< SYSTEM DESCRIPTION > [VK56VD]
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Component DescriptionINFOID:0000000006217657
1. ASCD steering switch
ICC steering switch 2. Snow mode switch 3. Fu INFINITI QX56 2011  Factory Service Manual 
COMPONENT PARTSEC-19
< SYSTEM DESCRIPTION > [VK56VD]
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Component DescriptionINFOID:0000000006217657
1. ASCD steering switch
ICC steering switch 2. Snow mode switch 3. Fu](/img/42/57033/w960_57033-2042.png)
COMPONENT PARTSEC-19
< SYSTEM DESCRIPTION > [VK56VD]
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Component DescriptionINFOID:0000000006217657
1. ASCD steering switch
ICC steering switch 2. Snow mode switch 3. Fuel level sensor unit and fuel pump 
assembly (with fuel tank temperature 
sensor)
4. Fuel pump control module (FPCM) 5. EVAP canister vent control valve 6. EVAP canister
7. EVAP control system pressure sen- sor 8. Stop lamp switch 9. ASCD brake switch
ICC brake switch
10. Accelerator pedal position sensor
JSBIA0606ZZ
Component Reference
ECM EC-23, "
ECM"
Malfunction indicator lamp (MIL)EC-30, "Malfunction Indicator Lamp (MIL)"
Ignition coil with power transistorEC-29, "Ignition Coil With Power Transistor"
Accelerator pedal position sensorEC-21, "Accelerator Pedal Position Sensor"
Mass air flow sensor
EC-31, "Mass Air Flow Sensor (With Intake Air Temperature Sen-
sor)"Intake air temperature sensor
Electric throttle control actuator
EC-23, "
Electric Throttle Control Actuator"Throttle control motor relay
Throttle control motor
Throttle position sensor
Crankshaft position sensorEC-23, "
Crankshaft Position Sensor"
Camshaft position sensorEC-22, "Camshaft Position Sensor"
Engine coolant temperature sensorEC-25, "Engine Coolant Temperature Sensor"
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EC-20
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
High pressure fuel pump
EC-28, "High Pressure Fuel Pump"
Low pressure fuel pumpEC-30, "Low Pressure Fuel Pump"
Fuel pump control module (FPCM)EC-2 INFINITI QX56 2011  Factory Service Manual 
EC-20
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
High pressure fuel pump
EC-28, "High Pressure Fuel Pump"
Low pressure fuel pumpEC-30, "Low Pressure Fuel Pump"
Fuel pump control module (FPCM)EC-2](/img/42/57033/w960_57033-2043.png)
EC-20
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
High pressure fuel pump
EC-28, "High Pressure Fuel Pump"
Low pressure fuel pumpEC-30, "Low Pressure Fuel Pump"
Fuel pump control module (FPCM)EC-27, "Fuel Pump Control Module"
Fuel rail pressure sensorEC-27, "Fuel Rail Pressure Sensor"
Low fuel pressure sensorEC-30, "Low Fuel Pressure Sensor"
Fuel injectorEC-26, "Fuel Injector"
Fuel level sensorEC-26, "Fuel Level Sensor"
Fuel tank temperature sensorEC-27, "Fuel Tank Temperature Sensor"
A/F sensor 1
EC-21, "Air Fuel Ratio (A/F) Sensor 1"A/F sensor 1 heater
Heated oxygen sensor 2EC-27, "
Heated Oxygen Sensor 2"Heated oxygen sensor 2 heater
Manifold absolute pressure sensorEC-31, "
Manifold Absolute Pressure Sensor"
Knock sensorEC-30, "Knock Sensor"
Engine oil temperature sensorEC-25, "Engine Oil Temperature Sensor"
Power steering pressure sensorEC-31, "Power Steering Pressure (PSP) Sensor"
Electrically-controlled cooling fan coupling EC-24, "Electrically-controlled cooling fan coupling"
Intake valve timing control solenoid valveEC-29, "Intake Valve Timing Control Solenoid Valve"
VVEL control moduleEC-32, "VVEL Control Module"
VVEL actuator motor relayEC-32, "VVEL Actuator Motor Relay"
VVEL actuator motorEC-32, "VVEL Actuator Motor"
VVEL control shaft position sensor EC-32, "VVEL Control Shaft Position Sensor"
EVAP control system pressure sensor EC-26, "EVAP Control System Pressure Sensor"
EVAP canister vent control valveEC-26, "EVAP Canister Vent Control Valve"
EVAP canister purge volume control solenoid valveEC-26, "EVAP Canister Purge Volume Control Solenoid Valve"
Battery current sensor (with battery temperature sensor)EC-22, "Battery Current Sensor (With Battery Temperature Sen-
sor)"
Refrigerant pressure sensor
EC-32, "Refrigerant Pressure Sensor"
Stop lamp switch
EC-21, "ASCD Brake Switch & Stop Lamp Switch"ASCD brake switch
ASCD steering switchEC-21, "
ASCD Steering Switch"
Information displayEC-49, "AUTMATIC SPEED CONTROL DEVICE (ASCD) : Switch 
Name and Function"
Stop lamp switch
EC-29, "ICC Brake Switch & Stop Lamp Switch"ICC brake switch
ICC steering switchEC-29, "
ICC Steering Switch"
Component Reference
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EC-32
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Refrigerant Pressure Sensor
INFOID:0000000006217690
The refrigerant pressure sensor is installed at the c ondenser of the air conditioner system.  INFINITI QX56 2011  Factory Service Manual 
EC-32
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Refrigerant Pressure Sensor
INFOID:0000000006217690
The refrigerant pressure sensor is installed at the c ondenser of the air conditioner system.](/img/42/57033/w960_57033-2055.png)
EC-32
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Refrigerant Pressure Sensor
INFOID:0000000006217690
The refrigerant pressure sensor is installed at the c ondenser 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.
VVEL Actuator MotorINFOID:0000000006217691
The VVEL actuator motor rotates the control shaft acco rding to the control signal from the VVEL control mod-
ule. The VVEL control module judges whether the VVEL  actuator motor controls the angle properly by the
VVEL control shaft position sensor signal.
VVEL Actuator Motor RelayINFOID:0000000006217692
Power supply for the VVEL actuator motor is provided  to the VVEL control module via VVEL actuator motor
relay. VVEL actuator motor relay is ON/OFF controll ed by the VVEL control module. In addition, when the
VVEL actuator motor relay cannot be controlled by the  VVEL control module for some reason, it ON/OFF con-
trolled by ECM.
VVEL Control ModuleINFOID:0000000006217693
The VVEL control module consists  of a microcomputer and connec-
tors for signal input and output and for power supply. The VVEL con-
trol module controls VVEL system.
VVEL Control Shaft Position SensorINFOID:0000000006217694
VVEL control shaft position sensor  detects the control shaft position
angle.
A magnet is installed to the tip of the control shaft.
The magnetic field changes as the control shaft rotates. This
changes output voltage of the VVEL control shaft position sensor.
VVEL control module detects the  actual position angle through the
voltage change and sends the signal to ECM.
PBIB2657E
JMBIA0879ZZ
JSBIA0466ZZ
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SYSTEMEC-47
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AIR CONDITIONING CUT CONTROL : System DiagramINFOID:0000000006217713
AIR CONDITIONING CUT CONTROL : System DescriptionINFOI INFINITI QX56 2011  Factory Service Manual 
SYSTEMEC-47
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AIR CONDITIONING CUT CONTROL : System DiagramINFOID:0000000006217713
AIR CONDITIONING CUT CONTROL : System DescriptionINFOI](/img/42/57033/w960_57033-2070.png)
SYSTEMEC-47
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AIR CONDITIONING CUT CONTROL : System DiagramINFOID:0000000006217713
AIR CONDITIONING CUT CONTROL : System DescriptionINFOID:0000000006217714
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
This system improves engine operation 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.
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
JMBIA1457GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor
Camshaft position sensor Engine speed*
2
Air conditioner cut 
controlIPDM E/R
↓
A/C relay
↓
Compressor
Engine coolant temperature sensor Engine coolant temperature
Accelerator pedal position sensor Accelerator pedal position
Battery
Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
A/C auto amp.A/C ON signal*
1
A/C evaporator temperature*1
Target A/C evaporator temperature*1
Blower fan ON signal
Combination meter Vehicle speed*
1
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DIAGNOSIS SYSTEM (ECM)EC-67
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OLOAD SIGNAL ON/OFF
 Indicates [ON/OFF] condition from the electrical 
load signal.
ON: Rear window defogger INFINITI QX56 2011  Factory Service Manual 
DIAGNOSIS SYSTEM (ECM)EC-67
< SYSTEM DESCRIPTION > [VK56VD]
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OLOAD SIGNAL ON/OFF
 Indicates [ON/OFF] condition from the electrical 
load signal.
ON: Rear window defogger](/img/42/57033/w960_57033-2090.png)
DIAGNOSIS SYSTEM (ECM)EC-67
< SYSTEM DESCRIPTION > [VK56VD]
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OLOAD SIGNAL ON/OFF
 Indicates [ON/OFF] condition from the electrical 
load signal.
ON: Rear window defogger switch is ON and/or 
lighting switch is in 2nd position.
OFF: Both rear window defogger switch and light-
ing switch are OFF.
IGNITION SW ON/OFF  Indicates [ON/OFF] condition from ignition switch 
signal.
HEATER FAN SW ON/OFF  Indicates [ON/OFF] condition from the blower fan 
ON signal.
BRAKE SW ON/OFF  Indicates [ON/OFF] condition from the stop lamp 
switch signal.
IGN TIMING BTDC  Indicates the ignition timing computed by ECM ac-
cording to the input signals.  When the engine is stopped, 
a certain value is indicated.
COMBUSTION —  These items are displayed but are not applicable to 
this model.
CAL/LD VALUE %  “Calculated load value” indicates the value of the 
current air flow divided by peak air flow.
MASS AIRFLOW g/s  Indicates the mass air flow computed by ECM ac-
cording to the signal voltage of the mass air flow 
sensor.
PURG VOL C/V %  Indicates the EVAP canister purge volume control 
solenoid valve control value computed by the ECM 
according to the input signals.
 The opening becomes larger as the value increas-
es.
INT/V SOL (B1)
% The control value of the intake valve timing control 
solenoid valve (determined by ECM according to 
the input signals) is indicated.
 The advance angle becomes larger as the value  increases.
INT/V SOL (B2)
AIR COND RLY ON/OFF
 The air conditioner relay control condition (deter-
mined by ECM according to the input signals) is in-
dicated.
VENT CONT/V ON/OFF  The control condition of the EVAP canister vent 
control valve (determined by ECM according to the 
input signals) is indicated.
ON: Closed
OFF: Open
THRTL RELAY ON/OFF  Indicates the throttle co
ntrol motor relay control 
condition determined by the ECM according to the 
input signals.
A/F S1 HTR (B1)
% Air fuel ratio (A/F) sensor 1 heater control value 
computed by ECM according to the input signals.
 The current flow to the heater becomes larger as  the value increases.
A/F S1 HTR (B2)
HO2S2 HTR (B1)
ON/OFF Indicates [ON/OFF] condition of heated oxygen 
sensor 2 heater determined by ECM according to 
the input signals.
HO2S2 HTR (B2)
ALT DUTY SIG ON/OFF  The control condition of the power generation volt-
age variable control (determined by ECM accord-
ing to the input signals) is indicated.
ON: Power generation voltage variable control is 
active.
OFF: Power generation voltage variable control is 
inactive.
I/P PULLY SPD rpm  Indicates the engine speed computed from the in-
put speed sensor signal.
Monitored item Unit Description Remarks
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EC-70
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: The item is indicated, but not used.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the displa INFINITI QX56 2011  Factory Service Manual 
EC-70
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: The item is indicated, but not used.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the displa](/img/42/57033/w960_57033-2093.png)
EC-70
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: The item is indicated, but not used.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
ECM TEMP 1
°C or  °F  Displays a temperature calculated from a signal of 
ECM temperature sensor 1.
ECM TEMP 2 °C or  °F  Displays a temperature calculated from a signal of 
ECM temperature sensor 2.
FUEL PUMP DUTY %  The control condition of the fuel pump control mod-
ule (FPCM) (determined by ECM according to the 
input signals) is indicated.
Monitored item Unit Description Remarks
TEST ITEM CONDITION JUDGMENT CHECK ITEM (REMEDY)
VENT CON-
TROL/V  Ignition switch: ON (Engine 
stopped)
 Turn solenoid valve ON and OFF  with the CONSULT-III and listen 
to operating sound. Solenoid valve makes an operating 
sound.
 Harness and connectors
 Solenoid valve
ENG COOLANT 
TEMP  Engine: Return to the original 
non-standard condition
 Change the engine coolant tem- perature using CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.  Harness and connectors
 Engine coolant temperature sen-
sor
 Fuel injector
FUEL INJEC-
TION  Engine: Return to the original 
non-standard condition
 Change the amount of fuel injec- tion using CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.
 Harness and connectors
 Fuel injector
 Air fuel ratio (A/F) sensor 1
FUEL/T TEMP 
SEN  Change the fuel tank temperature using CONSULT-III.
PURG VOL 
CONT/V  Engine: After warming up, run en-
gine at 1,500 rpm.
 Change the EVAP canister purge 
volume control solenoid valve 
opening percent using CON-
SULT-III. Engine speed changes according to 
the opening percent.
 Harness and connectors
 Solenoid valve
FAN DUTY CON-
TROL* Ignition switch: ON
 Change duty ratio using CON-
SULT-III. Cooling fan speed changes.  Harness and connectors
 Cooling fan motor
 Cooling fan relay
 Cooling fan control module
 IPDM E/R
ALTERNATOR 
DUTY Engine: Idle
 Change duty ratio using CON-
SULT-III. Battery voltage changes.  Harness and connectors
 IPDM E/R
Alternator
POWER BAL-
ANCE  Engine: After warming up, idle the 
engine.
 A/C switch OFF
 Selector lever: P or N
 Cut off each injector signal one at  a time using CONSULT-III. Engine runs rough or stops.
 Harness and connectors
 Compression
 Fuel injector
 Power transistor
Spark plug
 Ignition coil
IGNITION TIM-
ING  Engine: Return to the original 
non-standard condition
 Timing light: Set
 Retard the ignition timing using 
CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.
 Perform Idle Air Volume Learning.
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EC-74
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
INT/V SOL (B2) Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 0 - 2%
2,000 rpm Approx. 0 - 50%
AIR COND RL INFINITI QX56 2011  Factory Service Manual 
EC-74
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
INT/V SOL (B2) Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 0 - 2%
2,000 rpm Approx. 0 - 50%
AIR COND RL](/img/42/57033/w960_57033-2097.png)
EC-74
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
INT/V SOL (B2) Engine: After warming up
 Selector lever: P or N position
 A/C switch: OFF
No load Idle 0 - 2%
2,000 rpm Approx. 0 - 50%
AIR COND RLY  Engine: After warming up, idle 
the engine A/C switch: OFF OFF
A/C switch: ON
(Compressor operates)
ON
VENT CONT/V  Ignition switch: ON OFF
THRTL RELAY  Ignition switch: ON ON
A/F S1 HTR (B1)  Engine: After warming up, idle the engine
(More than 140 seconds after starting engine) 4 - 100%
A/F S1 HTR (B2)  Engine: After warming up, idle the engine
(More than 140 seconds after starting engine) 4 - 100%
HO2S2 HTR (B1)  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
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
ALT DUTY SIG  Power generation voltage variable control: Operating ON
 Power generation voltage variable control: Not operating OFF
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-III value with the speedometer in-
dication. Almost the same speed as 
the speedometer indication
IDL A/V LEARN  Engine: Running Idle air volume learning has not been per-
formed yet.
YET
Idle air volume learning has already been 
performed successfully. CMPLT
TRVL AFTER MIL  Ignition switch: ON Vehicle has traveled after MIL has illumi-
nated.0 - 65,535 km
(0 - 40,7
23 miles)
SNOW MODE SW  Ignition switch: ON Snow mode switch: ON ON
Snow mode switch: OFF OFF
ENG OIL TEMP  Engine: After warming up More than 70 °C (158 °F)
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
BRAKE SW1
(ASCD/ICC brake 
switch)  Ignition switch: ON
Brake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
Monitor Item Condition Values/Status
Revision: 2010 May2011 QX56  
Page 2114 of 5598
![INFINITI QX56 2011  Factory Service Manual 
EC-90
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
111
(R) 175
(B) Fuel injector driver power supply Input [Ignition  switch:  ON]
BATTERY VOLTAGE
(11 - 14 V)
11 2
(SB) 175
(B) Fuel injector driver powe INFINITI QX56 2011  Factory Service Manual 
EC-90
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
111
(R) 175
(B) Fuel injector driver power supply Input [Ignition  switch:  ON]
BATTERY VOLTAGE
(11 - 14 V)
11 2
(SB) 175
(B) Fuel injector driver powe](/img/42/57033/w960_57033-2113.png)
EC-90
< ECU DIAGNOSIS INFORMATION >[VK56VD]
ECM
111
(R) 175
(B) Fuel injector driver power supply Input [Ignition  switch:  ON]
BATTERY VOLTAGE
(11 - 14 V)
11 2
(SB) 175
(B) Fuel injector driver power supply Input [Ignition  switch:  ON] BATTERY VOLTAGE
(11 - 14 V)
11 4 (B) — ECM ground — — —
11 5 (B) — ECM ground — — —
120 (Y) 175
(B) EVAP canister vent control valve Output [Ignition  switch:  ON] BATTERY VOLTAGE
(11 - 14 V)
122
(BR/ W) 175
(B) VVEL actuator motor relay abort 
signal (VVEL control module)
Input [Ignition switch: ON] 0 V
123
(V/R) 175
(B) Throttle control mo
tor relay Output [Ignition switch: ON 
→ OFF] 0 - 1.0 V 
↓
BATTERY VOLTAGE 
(11 - 14 V) 
↓
0 V
[Ignition switch: ON] 0 - 1.0 V
125
(GR) 175
(B) Fuel pump control module
(FPCM)
Output[When cranking engine] 0 - 0.5 V
[Engine is running]
 Warm-up condition
0 - 4.0 V
126 (O) 129
(P/L) Accelerator pedal position sen-
sor 2
Input[Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully released
0.28 - 0.48 V
[Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully depressed 2.0 - 2.5 V
128 (Y) 130
(R) ASCD steering switch Input [Ignition switch: ON]
 ASCD steering switch: OFF
4 V
[Ignition switch: ON]
 MAIN switch: Pressed 0 V
[Ignition switch: ON]
 CANCEL switch: Pressed 1 V
[Ignition switch: ON]
 RESUME/ACCELERATE switch:  Pressed 3 V
[Ignition switch: ON]
 SET/COAST switch: Pressed 2 V
Te r m i n a l  N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
JPBIA3344ZZ
Revision: 2010 May2011 QX56