2009 INFINITI QX56 engine

ECM
EC-429
< ECU DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
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-
MI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)SEC986C
SEC987C
Revision: December 20092009 QX56

EC-430
< ECU DIAGNOSIS >[VK56DE]
ECM
99 G/RASCD steering switch
(Models with ASCD system) [Ignition switch: ON]
 ASCD steering switch: OFF
Approximately 4V
[Ignition switch: ON]
 MAIN switch: Pressed Approximately 0V
[Ignition switch: ON]
 CANCEL switch: Pressed Approximately 1V
[Ignition switch: ON]
 RESUME/ACCELERATE switch: Pressed Approximately 3V
[Ignition switch: ON]
 SET/COAST switch: Pressed Approximately 2V
101 R/W Stop lamp switch [Ignition switch: OFF]
 Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]
 Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
102 GR/R Transmission range signal [Ignition switch: ON]
 Selector lever: P or N
Approximately 0V
[Ignition switch: ON]
 Except the above gear position BATTERY VOLTAGE
(11 - 14V)
104 O Throttle cont rol motor relay[Ignition switch: OFF]
BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON] 0 - 1.0V
106 BR/W Accelerator pedal position
sensor 1 [Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully released
0.5 - 1.0V
[Ignition switch: ON]
 Engine: Stopped
 Accelerator pedal: Fully depressed 4.2 - 4.8V
107 V/R Fuel tank temperature sensor [Engine is running]Approximately 0 - 4.8V
Output voltage varies with fuel
tank temperature.
108 BR/W ICC brake switch
(Models with ICC system)
ASCD brake switch
(Models with ASCD system) [Ignition switch: ON]
 Brake pedal: Slightly depressed
Approximately 0V
[Ignition switch: ON]
 Brake pedal: Fully released BATTERY VOLTAGE
(11 - 14V)
109 L/W Ignition switch [Ignition switch: OFF]
0V
[Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
111 W / B ECM relay
(Self shut-off) [Engine is running]
[Ignition switch: OFF]
 For a few seconds after turning ignition
switch OFF 0 - 1.5V
[Ignition switch: OFF]
 More than a few seconds after turning igni- tion switch OFF BATTERY VOLTAGE
(11 - 14V)
113 GR Fuel pump relay [Ignition switch: ON]
 For 1 second after turning ignition switch
ON
[Engine is running] 0 - 1.5V
[Ignition switch: ON]
 More than 1 second after turning ignition switch ON BATTERY VOLTAGE
(11 - 14V)
TER-
MI-
NAL NO.
WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
Revision: December 20092009 QX56

ECM
EC-431
< ECU DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
*:Before measuring the terminal voltage, confir m that the battery is fully charged. Refer to PG-77
.
11 5
11 6
B
B/W
ECM ground [Engine is running]
 Idle speed Body ground
11 7 L / Y EVAP canister vent control
valve
[Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
11 9
120 BR
BR
Power supply for ECM
[Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
121 W Power supply for ECM
(Back-up) [Ignition switch: OFF] BATTERY VOLTAGE
(11 - 14V)
TER-
MI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
Revision: December 20092009 QX56

EC-432
< ECU DIAGNOSIS >[VK56DE]
ECM
Wiring Diagram - ENGINE CONTROL SYSTEM -
INFOID:0000000003771734
AABWA0099GB
Revision: December 20092009 QX56

EC-454
< ECU DIAGNOSIS >[VK56DE]
ECM
 When there is an open circuit on MIL circuit, the ECM c
annot warn the driver by lighting up MIL when there
is malfunction on engine control system.
Therefore, when electrical controlled throttle and pa rt of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engi ne control system malfunctions and MIL circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnos es except MIL circuit are detected and demands the
driver to repair the malfunction.
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118 Engine coolant tempera-
ture sensor circuit Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT-IIl displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-IIl display)
Just as ignition switch is turned ON
or START 40
°C (104 °F)
Approx 4 minutes or more after en-
gine starting. 80
°C (176 °F)
Except as shown above 40 - 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.
P0122
P0123
P0222
P0223
P2135 Throttle position sensor The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
P0643 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2100
P2103 Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2101 Electric throttle control function ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2118 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2119 Electric thro ttle control ac-
tuator (When electric throttle control actuator does not function properly due to the return spring
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the
idle position. The engine speed will not rise more than 2,000 rpm.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(When ECM detects the throttle valve is stuck open:)
While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops, the
engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or
more.
P2122
P2123
P2127
P2128
P2138 Accelerator pedal position
sensor
The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
Revision: December 20092009 QX56

ECM
EC-455
< ECU DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
DTC Inspection Priority ChartINFOID:0000000003771736
If some DTCs are displayed at the same time, per
form inspections one by one based on the following priority
chart.
NOTE:
 If DTC U1000 and/or U1001 is displayed with other DTC, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-86
.
 If DTC P0607 is displayed with ot her DTC, first perform the trouble diagnosis for DTC P0607. Refer to
EC-284
.
Priority Detected items (DTC)
1  U1000 U1001 CAN communication line  P0101 P0102 P0103 Mass air flow sensor
 P0112 P0113 P0127 Intake air temperature sensor
 P0116 P0117 P0118 P0125 Engine coolant temperature sensor
 P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor
 P0128 Thermostat function
 P0181 P0182 P0183 Fuel tank temperature sensor
 P0327 P0328 P0332 P0333 Knock sensor
 P0335 Crankshaft position sensor (POS)
 P0340 Camshaft posi tion sensor (PHASE)
 P0460 P0461 P0462 P0463 Fuel level sensor
 P0500 Vehicle speed sensor
 P0605 P0607 ECM
 P0643 Sensor power supply
 P0700 TCM
 P0705 Transmission range switch
 P0850 Park/neutral position (PNP) switch
 P1550 P1551 P1552 P1553 P1554 Battery current sensor
 P1610 - P1615 NATS
 P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
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
Revision: December 20092009 QX56

ECM
EC-461
< ECU DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
Procedures for clearing the DTC and the 1st trip DT
C from the ECM memory are described in "HOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION".
For malfunctions in which 1st trip DTCs are displa yed, refer to "EMISSION-RELATED DIAGNOSTIC INFOR-
MATION ITEMS". These items are required by legal r egulations to continuously monitor the system/compo-
nent. In addition, the items monitored non-cont inuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979. 1st trip DTC detection occurs without lighting up the MIL
and therefore does not warn the driver of a malfunction. However, 1st trip DTC detection will not prevent the
vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in Work Flow procedure Step 2, refer to EC-8, "Trouble Diagnosis Introduction"
. Then per-
form DTC Confirmation Procedure or Overall Function Che ck to try to duplicate the malfunction. If the mal-
function is duplicated, the item requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-III
With GST
CONSULT-III or GST (Generic Scan Tool ) Examples: P0340, P0850, P1148, etc.
These DTCs are prescribed by SAE J2012.
(CONSULT-III also displays the malfunctioning component or system.)
No Tools
The number of blinks of the MIL in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0340, 0850, 1148, etc.
These DTCs are controlled by NISSAN.
 1st trip DTC No. is the same as DTC No.
 Output of a DTC indicates a malfunc tion. However, GST or the Diagnostic Test Mode II do not indi-
cate whether the malfunction is stil l occurring or has occurred in the past and has returned to nor-
mal. CONSULT-III can identify malfunction status as shown below. Therefore, using CONSULT-III (if
available) is recommended.
DTC or 1st trip DTC of a malfunction is display ed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-III.
Time data indicates how many times the vehicle was driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be [0].
If a 1st trip DTC is stored in the ECM, the time data will be [1t].
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engi ne speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are ca lled freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame data can only be displa yed on the CONSULT-III screen, not on the GST. For
details, see EC-63, "CONSULT-III Function (ENGINE)"
.
Only one set of freeze frame data (either 1st trip freez e frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM me mory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
For example, the EGR malfunction (P riority: 2) was detected and the freeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st tr ip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If fr eeze frame data is stored in the ECM memory and freeze
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
Revision: December 20092009 QX56