2004 INFINITI QX56 heater

EC-4Revision: August 20072004 QX56 Overall Function Check ........................................326
Diagnostic Procedure ...........................................327
DTC P0460 FUEL LEVEL SENSOR .......................334
Component Description ........................................334
On Board Diagnosis Logic ....................................334
DTC Confirmation Procedure ...............................334
Diagnostic Procedure ...........................................335
Removal and Installation ......................................335
DTC P0461 FUEL LEVEL SENSOR .......................336
Component Description ........................................336
On Board Diagnosis Logic ....................................336
Overall Function Check ........................................336
Diagnostic Procedure ...........................................337
Removal and Installation ......................................337
DTC P0462, P0463 FUEL LEVEL SENSOR CIR-
CUIT ........................................................................338
Component Description ........................................338
On Board Diagnosis Logic ....................................338
DTC Confirmation Procedure ...............................338
Diagnostic Procedure ...........................................339
Removal and Installation ......................................339
DTC P0500 VSS ......................................................340
Description ............................................................340
On Board Diagnosis Logic ....................................340
DTC Confirmation Procedure ...............................340
Overall Function Check ........................................340
Diagnostic Procedure ...........................................341
DTC P0506 ISC SYSTEM .......................................342
Description ............................................................342
On Board Diagnosis Logic ....................................342
DTC Confirmation Procedure ...............................342
Diagnostic Procedure ...........................................343
DTC P0507 ISC SYSTEM .......................................344
Description ............................................................344
On Board Diagnosis Logic ....................................344
DTC Confirmation Procedure ...............................344
Diagnostic Procedure ...........................................345
DTC P0550 PSP SENSOR ......................................346
Component Description ........................................346
CONSULT-II Reference Value in Data Monitor Mode
.346
On Board Diagnosis Logic ....................................346
DTC Confirmation Procedure ...............................346
Wiring Diagram .....................................................347
Diagnostic Procedure ...........................................348
Component Inspection ..........................................350
Removal and Installation ......................................350
DTC P0605 ECM .....................................................351
Component Description ........................................351
On Board Diagnosis Logic ....................................351
DTC Confirmation Procedure ...............................351
Diagnostic Procedure ...........................................352
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1
HEATER ..................................................................354
Description ............................................................354
CONSULT-II Reference Value in Data Monitor Mode
.354
On Board Diagnosis Logic ....................................354
DTC Confirmation Procedure ...............................354Wiring Diagram ..................................................... 355
Diagnostic Procedure ............................................ 358
Component Inspection .......................................... 360
Removal and Installation ....................................... 360
DTC P1065 ECM POWER SUPPLY ........................ 361
Component Description ........................................ 361
On Board Diagnosis Logic .................................... 361
DTC Confirmation Procedure ................................ 361
Wiring Diagram ..................................................... 362
Diagnostic Procedure ............................................ 363
DTC P1121 ELECTRIC THROTTLE CONTROL
ACTUATOR ............................................................. 365
Component Description ........................................ 365
On Board Diagnosis Logic .................................... 365
DTC Confirmation Procedure ................................ 365
Diagnostic Procedure ............................................ 366
DTC P1122 ELECTRIC THROTTLE CONTROL
FUNCTION .............................................................. 367
Description ............................................................ 367
On Board Diagnosis Logic .................................... 367
DTC Confirmation Procedure ................................ 367
Wiring Diagram ..................................................... 368
Diagnostic Procedure ............................................ 369
Component Inspection .......................................... 372
Remove and Installation ....................................... 372
DTC P1124, P1126 THROTTLE CONTROL MOTOR
RELAY ..................................................................... 373
Component Description ........................................ 373
CONSULT-II Reference Value in Data Monitor Mode
. 373
On Board Diagnosis Logic .................................... 373
DTC Confirmation Procedure ................................ 373
Wiring Diagram ..................................................... 375
Diagnostic Procedure ............................................ 376
DTC P1128 THROTTLE CONTROL MOTOR ......... 378
Component Description ........................................ 378
On Board Diagnosis Logic .................................... 378
DTC Confirmation Procedure ................................ 378
Wiring Diagram ..................................................... 379
Diagnostic Procedure ............................................ 380
Component Inspection .......................................... 381
Removal and Installation ....................................... 382
DTC P1146, P1166 HO2S2 ..................................... 383
Component Description ........................................ 383
CONSULT-II Reference Value in Data Monitor Mode
. 383
On Board Diagnosis Logic .................................... 383
DTC Confirmation Procedure ................................ 384
Overall Function Check ......................................... 384
Wiring Diagram ..................................................... 386
Diagnostic Procedure ............................................ 389
Component Inspection .......................................... 392
Removal and Installation ....................................... 394
DTC P1147, P1167 HO2S2 ..................................... 395
Component Description ........................................ 395
CONSULT-II Reference Value in Data Monitor Mode
. 395
On Board Diagnosis Logic .................................... 395
DTC Confirmation Procedure ................................ 396

EC-7
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Revision: August 20072004 QX56 Component Inspection ......................................... 582
Removal and Installation ...................................... 582
IGNITION SIGNAL .................................................. 583
Component Description ........................................ 583
Wiring Diagram .................................................... 584
Diagnostic Procedure ........................................... 589
Component Inspection ......................................... 593
Removal and Installation ...................................... 594
INJECTOR CIRCUIT ............................................... 595
Component Description ........................................ 595
CONSULT-II Reference Value in Data Monitor Mode
. 595
Wiring Diagram .................................................... 596
Diagnostic Procedure ........................................... 597
Component Inspection ......................................... 600
Removal and Installation ...................................... 600
FUEL PUMP CIRCUIT ............................................ 601
Description ........................................................... 601
CONSULT-II Reference Value in Data Monitor Mode
. 601
Wiring Diagram .................................................... 602
Diagnostic Procedure ........................................... 603
Component Inspection ......................................... 606
Removal and Installation ...................................... 606
REFRIGERANT PRESSURE SENSOR ................. 607
Component Description ........................................ 607
Wiring Diagram .................................................... 608
Diagnostic Procedure ........................................... 609
Removal and Installation ....................................... 611
ELECTRICAL LOAD SIGNAL ................................ 612
Description ........................................................... 612
CONSULT-II Reference Value in Data Monitor Mode
. 612
Diagnostic Procedure ........................................... 612
ICC BRAKE SWITCH ............................................. 613
Component Description ........................................ 613
CONSULT-II Reference Value in Data Monitor Mode
. 613
Wiring Diagram .................................................... 614
Diagnostic Procedure ........................................... 615
Component Inspection ......................................... 619
ASCD BRAKE SWITCH ......................................... 621
Component Description ........................................ 621CONSULT-II Reference Value in Data Monitor Mode
.621
Wiring Diagram .....................................................622
Diagnostic Procedure ...........................................623
Component Inspection ..........................................627
ASCD INDICATOR ..................................................628
Component Description ........................................628
CONSULT-II Reference Value in Data Monitor Mode
.628
Wiring Diagram .....................................................629
Diagnostic Procedure ...........................................630
MIL AND DATA LINK CONNECTOR ......................631
Wiring Diagram .....................................................631
EVAPORATIVE EMISSION SYSTEM .....................633
Description ............................................................633
Component Inspection ..........................................636
Removal and Installation ......................................637
How to Detect Fuel Vapor Leakage ......................637
ON BOARD REFUELING VAPOR RECOVERY
(ORVR) ....................................................................640
System Description ...............................................640
Diagnostic Procedure ...........................................641
Component Inspection ..........................................643
POSITIVE CRANKCASE VENTILATION ...............645
Description ............................................................645
Component Inspection ..........................................645
AUTOMATIC SPEED CONTROL DEVICE (ASCD) .647
System Description ...............................................647
Component Description ........................................648
SERVICE DATA AND SPECIFICATIONS (SDS) ....649
Fuel Pressure .......................................................649
Idle Speed and Ignition Timing .............................649
Calculated Load Value ..........................................649
Mass Air Flow Sensor ...........................................649
Intake Air Temperature Sensor .............................649
Engine Coolant Temperature Sensor ...................649
A/F Sensor 1 Heater .............................................649
Heated Oxygen sensor 2 Heater ..........................649
Crankshaft Position Sensor (POS) .......................649
Camshaft Position Sensor (PHASE) ....................649
Throttle Control Motor ...........................................649
Injector ..................................................................650
Fuel Pump ............................................................650

ENGINE CONTROL SYSTEM
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System ChartUBS00GZD
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This sensor is not used to control the engine system under normal conditions.
*3: This input signal is sent to the ECM through CAN communication line.
*4: This output signal is sent from the ECM through CAN communication line.Input (Sensor) ECM Function Output (Actuator)

Camshaft position sensor (PHASE)

Crankshaft position sensor (POS)

Mass air flow sensor

Engine coolant temperature sensor

A/F sensor 1

Throttle position sensor

Accelerator pedal position sensor

Park/neutral position (PNP) switch

Intake air temperature sensor

Power steering pressure sensor

Ignition switch

Battery voltage

Knock sensor

Refrigerant pressure sensor

Stop lamp switch

ASCD steering switch

ASCD brake switch

Fuel level sensor*1 *3

EVAP control system pressure sensor

Fuel tank temperature sensor*1

Heated oxygen sensor 2*2

TCM (Transmission control module)*3

ABS actuator and electric unit (control unit)*3

Air conditioner switch*3

Wheel sensor*3

Electrical load signal*3
Fuel injection & mixture ratio control Fuel injector
Electronic ignition system Power transistor
Nissan torque demand control system

Electric throttle control actuator

Fuel injector
Fuel pump control Fuel pump relay
ASCD vehicle speed control Electric throttle control actuator
On board diagnostic system
MIL (On the instrument panel)*
4
A/F sensor 1 heater control A/F sensor 1 heater
Heated oxygen sensor 2 heater control Heated oxygen sensor 2 heater
EVAP canister purge flow controlEVAP canister purge volume control
solenoid valve
Air conditioning cut control
Air conditioner relay*
4
Cooling fan control
Cooling fan relay*4
ON BOARD DIAGNOSIS for EVAP system EVAP canister vent control valve

BASIC SERVICE PROCEDURE
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3. Check ignition timing.
Idle Speed/Ignition Timing/Idle Mixture Ratio AdjustmentUBS00GZL
PREPARATION
1. Make sure that the following parts are in good order.

Battery

Ignition system

Engine oil and coolant levels

Fuses

ECM harness connector

Vacuum hoses

Air intake system
(Oil filler cap, oil level gauge, etc.)

Fuel pressure

Engine compression

Throttle valve

Evaporative emission system
2. On air conditioner equipped models, checks should be carried out while the air conditioner is OFF.
3. On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio,
checks should be carried out while shift lever is in N position.
4. When measuring CO percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
5. Turn off headlamp, heater blower, rear window defogger.
6. Keep front wheels pointed straight ahead.
SEF 0 11V
BBIA0379E

EC-56Revision: August 2007
ON BOARD DIAGNOSTIC (OBD) SYSTEM
2004 QX56
*1: If completion of several SRTs is required, perform driving patterns (DTC confirmation procedure), one by one based on the pri ority for
models with CONSULT-II.
SRT Set Timing
SRT is set as “CMPLT” after self-diagnosis has been performed one or more times. Completion of SRT is
done regardless of whether the result is OK or NG. The set timing is different between OK and NG results and
is shown in the table below.
OK: Self-diagnosis is carried out and the result is OK.
NG: Self-diagnosis is carried out and the result is NG.
—: Self-diagnosis is not carried out.
When all SRT related self-diagnoses showed OK results in a single cycle (Ignition OFF-ON-OFF), the SRT will
indicate “CMPLT”. → Case 1 above
When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indicate
“CMPLT” at the time the respective self-diagnoses have at least one OK result. → Case 2 above
If one or more SRT related self-diagnoses showed NG results in 2 consecutive cycles, the SRT will also indi-
cate “CMPLT”. → Case 3 above
The table above shows that the minimum number of cycles for setting SRT as “INCMP” is one (1) for each
self-diagnosis (Case 1 & 2) or two (2) for one of self-diagnoses (Case 3). However, in preparation for the state
emissions inspection, it is unnecessary for each self-diagnosis to be executed twice (Case 3) for the following
reasons:

The SRT will indicate “CMPLT” at the time the respective self-diagnoses have one (1) OK result.

The emissions inspection requires “CMPLT” of the SRT only with OK self-diagnosis results.

When, during SRT driving pattern, 1st trip DTC (NG) is detected prior to “CMPLT” of SRT, the self-diagno-
sis memory must be erased from ECM after repair.

If the 1st trip DTC is erased, all the SRT will indicate “INCMP”.
NOTE:
SRT can be set as “CMPLT” together with the DTC(s). Therefore, DTC check must always be carried out
prior to the state emission inspection even though the SRT indicates “CMPLT”.
HO2S HTR 2 A/F sensor 1 heater P1031, P1032,
P1051, P1052
Heated oxygen sensor 2 heater P0037, P0038,
P0057, P0058 Item
(CONSULT-II indication)Performance
Priority
*1Required self-diagnostic items to set the SRT to “CMPLT”Corresponding DTC
No.
Self-diagnosis resultExample
DiagnosisIgnition cycle
← ON → OFF ← ON → OFF ← ON → OFF ← ON →
All OK Case 1 P0400 OK (1) — (1) OK (2) — (2)
P0402 OK (1) — (1) — (1) OK (2)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “CMPLT” “CMPLT” “CMPLT” “CMPLT”
Case 2 P0400 OK (1) — (1) — (1) — (1)
P0402 — (0) — (0) OK (1) — (1)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “INCMP” “INCMP” “CMPLT” “CMPLT”
NG exists Case 3 P0400 OK OK — —
P0402 — — — —
P1402 NG — NGNG
(Consecutive
NG)
(1st trip)
DTC1st trip DTC — 1st trip DTCDTC
(= MIL “ON”)
SRT of EGR “INCMP” “INCMP” “INCMP” “CMPLT”

ON BOARD DIAGNOSTIC (OBD) SYSTEM
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EVAPORA-
TIVE
SYSTEMEVAP control system (Small leak) P0442 05H 03H Max.
1/128mm2
EVAP control system purge flow monitoring P0441 06H 83H Min. 20mV
EVAP control system (Very small leak) P0456 07H 03H Max.
1/128mm
2
HO2SA/F sensor 1 (Bank 1)P1271 41H 8EH Min. 5 mV
P1272 42H 0EH Max. 5 mV
P1273 43H 0EH Max. 0.002
P1274 44H 8EH Min. 0.002
P1278 45H 8EH Min. 0.004
P1276 46H 0EH Max. 5 mV
P1276 47H 8EH Min. 5 mV
P1279 48H 8EH Min. 0.004
A/F sensor 1 (Bank 2)P1281 4CH 8FH Min. 5 mV
P1282 4DH 0FH Max. 5 mV
P1283 4EH 0FH Max. 0.002
P1284 4FH 8FH Min. 0.002
P1288 50H 8FH Min. 0.004
P1286 51H 0FH Max. 5 mV
P1286 52H 8FH Min. 5 mV
P1289 53H 8FH Min. 0.004
Heated oxygen sensor 2 (Bank 1)P0139 19H 86H Min. 10mV/500ms
P1147 1AH 86H Min. 10mV
P1146 1BH 06H Max. 10mV
P0138 1CH 06H Max. 10mV
Heated oxygen sensor 2 (Bank 2)P0159 21H 87H Min. 10mV/500ms
P1167 22H 87H Min. 10mV
P1166 23H 07H Max. 10mV
P0158 24H 07H Max. 10mV
HO2S HTRA/F sensor 1 heater (Bank 1)P1032 57H 10H Max. 5 mV
P1031 58H 90H Min. 5 mV
A/F sensor 1 heater (Bank 2)P1052 59H 11H Max. 5 mV
P1051 5AH 91H Min. 5 mV
Heated oxygen sensor 2 heater (Bank 1)P0038 2DH 0AH Max. 20mV
P0037 2EH 8AH Min. 20mV
Heated oxygen sensor 2 heater (Bank 2)P0058 2FH 0BH Max. 20mV
P0057 30H 8BH Min. 20mV SRT item Self-diagnostic test item DTCTest value (GST display)
Test limit Conversion
TID CID

TROUBLE DIAGNOSIS
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Fail-safe ChartUBS00GZY
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.
2
P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater

P0138 P0139 P0158 P0159 P1146 P1147 P1166 P1167 Heated oxygen sensor 2

P0441 EVAP control system purge flow monitoring

P0444 P0445 P1444 EVAP canister purge volume control solenoid valve

P0447 P1446 EVAP canister vent control valve

P0451 P0452 P0453 EVAP control system pressure sensor

P0550 Power steering pressure sensor

P0700 P0710 P0720 P0740 P0744 P0745 P1706 P1716 P1730 P1752 P1754 P1757 P1759 P1762 P1764 P1767
P1769 P1772 P1774 A/T related sensors and solenoid valves

P1031 P1032 P1051 P1052 A/F sensor 1 heater

P1065 ECM power supply

P1122 Electric throttle control function

P1124 P1126 P1128 Electric throttle control actuator

P1217 Engine over temperature (OVERHEAT)

P1271 P1272 P1273 P1274 P1276 P1278 P1279 P1281 P1282 P1283 P1284 P1286 P1288 P1289 A/F sensor 1

P1805 Brake switch
3

P0171 P0172 P0174 P0175 Fuel injection system function

P0300 - P0308 Misfire

P0420 P0430 Three way catalyst function

P0442 P0456 EVAP control system (SMALL LEAK, VERY SMALL LEAK)

P0455 EVAP control system (GROSS LEAK)

P0506 P0507 Idle speed control system

P1121 Electric throttle control actuator

P1148 P1168 Closed loop control

P1211 TCS control unit

P1212 TCS communication line

P1564 ICC steering switch/ASCD steering switch

P1568 ICC command value

P1572 ICC brake switch/ASCD brake switch

P1574 ICC vehicle speed sensor/ASCD vehicle speed sensor Priority Detected items (DTC)
DTC No. Detected items Engine operating condition in fail-safe mode
P0101
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or START40°C (104°F)
More than approx. 4 minutes after
ignition ON or START80°C (176°F)
Except as shown above40 - 80°C (104 - 176°F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling
fan operates while engine is running.

EC-96Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
ECM Harness Connector Terminal LayoutUBS00H03
ECM Terminals and Reference ValueUBS00H04
PREPARATION
1. ECM is located in the engine room passenger side behind bat-
tery.
2. Remove ECM harness connector.
3. When disconnecting ECM harness connector, loosen it with
levers as far as they will go as shown in the figure.
4. Connect a break-out box (SST) and Y-cable adapter (SST)
between the ECM and ECM harness connector.

Use extreme care not to touch 2 pins at one time.

Data is for comparison and may not be exact.
ECM INSPECTION TABLE
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.
PBIB1192E
BBIA0386E
BBIA0387E
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 B ECM ground[Engine is running]

Idle speedBody ground
2O/BA/F sensor 1 heater
(bank 1)[Engine is running]

Warm-up condition

Idle speedApproximately 5V
PBIB1584E