2004 INFINITI QX56 Can communication

EC-8Revision: August 2007
INDEX FOR DTC
2004 QX56
INDEX FOR DTCPFP:00024
Alphabetical IndexUBS00GZ3
NOTE:
If DTC U1000 or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
×:Applicable —: Not applicable
Items
(CONSULT-II screen terms)DTC*
1
TripMIL lighting
upReference page
CONSULT-II
GST*
2ECM*3
A/F SEN1 (B1) P1271 1271 2×EC-429
A/F SEN1 (B1) P1272 1272 2×EC-437
A/F SEN1 (B1) P1273 1273 2×EC-445
A/F SEN1 (B1) P1274 1274 2×EC-454
A/F SEN1 (B1) P1276 1276 2×EC-463
A/F SEN1 (B1) P1278 1278 2×EC-472
A/F SEN1 (B1) P1279 1279 2×EC-484
A/F SEN1 (B2) P1281 1281 2×EC-429
A/F SEN1 (B2) P1282 1282 2×EC-437
A/F SEN1 (B2) P1283 1283 2×EC-445
A/F SEN1 (B2) P1284 1284 2×EC-454
A/F SEN1 (B2) P1286 1286 2×EC-463
A/F SEN1 (B2) P1288 1288 2×EC-472
A/F SEN1 (B2) P1289 1289 2×EC-484
A/F SEN1 HTR (B1) P1031 1031 2×EC-354
A/F SEN1 HTR (B1) P1032 1032 2×EC-354
A/F SEN1 HTR (B2) P1051 1051 2×EC-354
A/F SEN1 HTR (B2) P1052 1052 2×EC-354
ACC COMMAND VALUE*7P1568 1568 1 —EC-524
A/T INTERLOCK P1730 1730 1×AT-139
A/T TCC S/V FNCTN P0744 0744 2×AT-121
APP SEN 1/CIRC P2122 2122 1×EC-556
APP SEN 1/CIRC P2123 2123 1×EC-556
APP SEN 2/CIRC P2127 2127 1×EC-562
APP SEN 2/CIRC P2128 2128 1×EC-562
APP SENSOR P2138 2138 1×EC-576
ASCD BRAKE SW P1572 1572 1 —EC-525, EC-534
ASCD SW P1564 1564 1 —EC-510, EC-517
ASCD VHL SPD SEN*6P1574 1574 1 —EC-542, EC-544
ATF TEMP SEN/CIRC P0710 0710 2×AT-131
BRAKE SW/CIRCUIT P1805 1805 2 —EC-551
CAN COMM CIRCUIT U1000
1000*41×EC-135
CAN COMM CIRCUIT U1001
1001*42—EC-135
CKP SEN/CIRCUIT P0335 0335 2×EC-255
CLOSED LOOP-B1 P1148 1148 1×EC-407
CLOSED LOOP-B2 P1168 1168 1×EC-407

EC-12Revision: August 2007
INDEX FOR DTC
2004 QX56
DTC No. IndexUBS00GZ4
NOTE:
If DTC U1000 or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
×:Applicable —: Not applicable
DTC*
1
Items
(CONSULT-II screen terms)TripMIL lighting
upReference page
CONSULT-II
GST*
2ECM*3
U1000
1000*4CAN COMM CIRCUIT 1×EC-135
U1001
1001*4CAN COMM CIRCUIT 2 —EC-135
P0000 0000NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED.———
P0037 0037 HO2S2 HTR (B1) 2×EC-138
P0038 0038 HO2S2 HTR (B1) 2×EC-138
P0057 0057 HO2S2 HTR (B2) 2×EC-138
P0058 0058 HO2S2 HTR (B2) 2×EC-138
P0101 0101 MAF SEN/CIRCUIT 1×EC-146
P0102 0102 MAF SEN/CIRCUIT 1×EC-154
P0103 0103 MAF SEN/CIRCUIT 1×EC-154
P 0 11 2 0 11 2 I AT S E N /C I R C U I T 2×EC-161
P 0 11 3 0 11 3 I AT S E N /C I R C U I T 2×EC-161
P0117 0117 ECT SEN/CIRCUIT 1×EC-165
P0118 0118 ECT SEN/CIRCUIT 1×EC-165
P0122 0122 TP SEN 2/CIRC 1×EC-171
P0123 0123 TP SEN 2/CIRC 1×EC-171
P0125 0125 ECT SENSOR 1×EC-178
P0127 0127 IAT SENSOR 2×EC-181
P0128 0128 THERMSTAT FNCTN 2×EC-184
P0138 0138 HO2S2 (B1) 2×EC-186
P0139 0139 HO2S2 (B1) 2×EC-196
P0158 0158 HO2S2 (B2) 2×EC-186
P0159 0159 HO2S2 (B2) 2×EC-196
P0171 0171 FUEL SYS-LEAN-B1 2×EC-208
P0172 0172 FUEL SYS-RICH-B1 2×EC-217
P0174 0174 FUEL SYS-LEAN-B2 2×EC-208
P0175 0175 FUEL SYS-RICH-B2 2×EC-217
P0181 0181 FTT SENSOR 2×EC-225
P0182 0182 FTT SEN/CIRCUIT 2×EC-231
P0183 0183 FTT SEN/CIRCUIT 2×EC-231
P0222 0222 TP SEN 1/CIRC 1×EC-236
P0223 0223 TP SEN 1/CIRC 1×EC-236
P0300 0300 MULTI CYL MISFIRE 2×EC-243
P0301 0301 CYL 1 MISFIRE 2×EC-243
P0302 0302 CYL 2 MISFIRE 2×EC-243
P0303 0303 CYL 3 MISFIRE 2×EC-243

ENGINE CONTROL SYSTEM
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Revision: August 20072004 QX56
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

EC-26Revision: August 2007
ENGINE CONTROL SYSTEM
2004 QX56
Multiport Fuel Injection (MFI) SystemUBS00GZE
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*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). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor (POS), camshaft
position sensor (PHASE) and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated 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
A/F sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch 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)*
2VDC/TCS operation command
Air conditioner switch*
2Air conditioner operation
Wheel sensor*
2Vehicle speed

EC-28Revision: August 2007
ENGINE CONTROL SYSTEM
2004 QX56
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all eight cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The eight injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
Electronic Ignition (EI) SystemUBS00GZF
INPUT/OUTPUT SIGNAL CHART
*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 DESCRIPTION
The ignition timing is controlled by the ECM to maintain the best air-
fuel ratio for every running condition of the engine. The ignition tim-
ing data is stored in the ECM. This data forms the map shown.
The ECM receives information such as the injection pulse width and
camshaft position sensor signal. Computing this information, ignition
signals are transmitted to the power transistor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
A °BTDC
During the following conditions, the ignition timing is revised by the
ECM according to the other data stored in the ECM.

At starting

During warm-up
PBIB0122E
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
2
Piston position
Ignition timing
controlPower transistor Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Knock sensor Engine knocking
Park/neutral position (PNP) switch Gear position
Battery
Battery voltage*
2
Wheel sensor*1Vehicle speed
SEF 7 42 M

ENGINE CONTROL SYSTEM
EC-29
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Revision: August 20072004 QX56

At idle

At low battery voltage

During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Nissan Torque Demand (NTD) Control SystemUBS00GZG
INPUT/OUTPUT SIGNAL CHART
*1: Signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
NTD control system decides the target traction based on the accelerator operation status and the current driv-
ing condition. It then selects the engine torque target by correcting running resistance and atmospheric pres-
sure, and controlling the power-train. Using electric throttle control actuator, it achieves the engine torque
development target which corresponds linearly to the driver's accelerator operation.
Running resistance correction control compares the engine torque estimate value, measured vehicle acceler-
ation, and running resistance on a flat road, and estimates vehicle weight gain and running resistance varia-
tion caused by slopes to correct the engine torque estimate value.
Atmospheric pressure correction control compares the engine torque estimate value from the airflow rate and
the target engine torque for the target traction, and estimates variation of atmospheric pressure to correct the
target engine torque. This system achieves powerful driving without reducing engine performance in the prac-
tical speed range in mountains and high-altitude areas.
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
NTD controlElectric throttle con-
trol actuator and fuel
injector Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/Neutral position (PNP) switch Gear position
Power steering pressure sensor Power steering operation
Battery Battery voltage
TCM (CAN communication) A/T control signal
Air conditioner switch*
1Air conditioner operation
ABS actuator and electric unit (control unit)*
1VDC/TCS/ABS operation
Wheel sensor*
1Vehicle speed
Electrical load*
1Electrical load signal

EC-30Revision: August 2007
ENGINE CONTROL SYSTEM
2004 QX56
Air Conditioning Cut ControlUBS00GZH
INPUT/OUTPUT SIGNAL CHART
*1: 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 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.
Fuel Cut Control (at No Load and High Engine Speed)UBS00GZI
INPUT/OUTPUT SIGNAL CHART
*1: Signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,400 rpm under no load (for example, the shift position is neutral and engine
speed is over 1,400 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies
based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,000 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under Multiport Fuel Injection (MFI) System, EC-26
.
Sensor Input signal to ECM ECM function Actuator
Air conditioner switch*
1Air conditioner ON signal
Air conditioner
cut controlAir conditioner relay Throttle position sensor Throttle position
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*
1Vehicle speed
Sensor Input signal to ECM ECM function Actuator
Park/neutral position (PNP) switch Neutral position
Fuel cut control Fuel injector Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed
Wheel sensor*
1Vehicle speed

ENGINE CONTROL SYSTEM
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Revision: August 20072004 QX56
CAN communicationUBS00GZJ
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Refer to LAN-5, "
CAN Communication Unit" , about CAN communication for detail.