2007 INFINITI QX56 change time

EC-30
< SERVICE INFORMATION >
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System DescriptionINFOID:0000000003531591
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 driver 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 throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator 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 indicator 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 reaches 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 the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp 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 lamp 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
Park/neutral position (PNP) switch Gear position
Wheel sensor Vehicle speed*
TCM Powertrain revolution*

EC-54
< SERVICE INFORMATION >
ON BOARD DIAGNOSTIC (OBD) SYSTEM
A sample of CONSULT-II display for DTC and 1st trip DTC is shown below. DTC or 1st trip DTC of a malfunc-
tion is displayed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-II. 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, engine 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 called freeze frame data and displayed on CONSULT-II or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
details, see E C - 111 , "
CONSULT-II Function (ENGINE)".
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory 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 (Priority: 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 trip 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 freeze frame data is stored in the ECM memory and freeze
frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged in the
ECM memory.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM mem-
ory is erased. Procedures for clearing the ECM memory are described in "HOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATION".
SYSTEM READINESS TEST (SRT) CODE
System Readiness Test (SRT) code is specified in Service $01 of SAE J1979.
As part of an enhanced emissions test for Inspection & Maintenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has completed self-diagnosis of major emission systems and com-
ponents. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspection due to one or more SRT items indicating “INCMP”, use
the information in this Service Manual to set the SRT to “CMPLT”.
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate “CMPLT” for each application system. Once set as “CMPLT”, the SRT status remains
“CMPLT” until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate “INCMP” for these items.
PBIB0911E
Priority Items
1Freeze 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

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-65
< SERVICE INFORMATION >
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displayed, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These uniden-
tified codes can be identified by using the CONSULT-II or GST. A DTC will be used as an example for how to
read a code.
A particular trouble code can be identified by the number of four-digit numeral flashes. The “zero” is indicated
by the number of ten flashes. The “A” is indicated by the number of eleven flash.The length of time the
1,000th-digit numeral flashes on and off is 1.2 seconds consisting of an ON (0.6-second) - OFF (0.6-second)
cycle.
The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.
A change from one digit numeral to another occurs at an interval of 1.0-second OFF. In other words, the later
numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8-second OFF.
In this way, all the detected malfunctions are classified by their DTC numbers. The DTC 0000 refers to no mal-
function. (See EC-9
)
How to Erase Diagnostic Test Mode II (Self-diagnostic Results)
The DTC can be erased from the back up memory in the ECM by depressing accelerator pedal. Refer to "How
to Erase Diagnostic Test Mode II (Self-diagnostic Results)".
•If the battery is disconnected, the DTC will be lost from the backup memory within 24 hours.
•Be careful not to erase the stored memory before starting trouble diagnoses.
OBD System Operation ChartINFOID:0000000003531608
RELATIONSHIP BETWEEN MIL, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMS
• When a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
• When the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MIL will come on. For details, refer to EC-48, "
Two Trip Detection Logic".
• The MIL will go off after the vehicle is driven 3 times (driving pattern B) with no malfunction. The drive is
counted only when the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs
while counting, the counter will reset.
• The DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A) with-
out the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel Injec-
PBIB3005E

EC-80
< SERVICE INFORMATION >
BASIC SERVICE PROCEDURE
3.Check that downstream of throttle valve is free from air leakage.
4.When the above three items check out OK, engine component parts and their installation condi-
tion are questionable. Check and eliminate the cause of the incident.
It is useful to perform EC-129
.
5.If any of the following conditions occur after the engine has started, eliminate the cause of the
incident and perform Idle Air Volume Learning all over again:
•Engine stalls.
•Erroneous idle.
Fuel Pressure CheckINFOID:0000000003531616
FUEL PRESSURE RELEASE
With CONSULT-II
1. Turn ignition switch ON.
2. Perform “FUEL PRESSURE RELEASE” in “WORK SUPPORT”
mode with CONSULT-II.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch OFF.
Without CONSULT-II
1. Remove fuel pump fuse located in IPDM E/R.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch OFF.
5. Reinstall fuel pump fuse after servicing fuel system.
FUEL PRESSURE CHECK
CAUTION:
• Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.
• Be careful not to scratch or get the fuel hose connection area dirty when servicing, so that the quick
connector o-ring maintains sealability.
• Use Fuel Pressure Gauge Kit J-44321 and Fuel Pressure Adapter J-44321-6 to check fuel pressure.
• Do not perform fuel pressure check with electrical system operating (i.e. lights, rear defog, A/C, etc.).
Fuel pressure gauge may indicate false readings due to varying engine loads and changes in mani-
fold vacuum.
NOTE:
Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel pres-
sure cannot be completely released because JA60 models do not have fuel return system.
1. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE" .
2. Remove engine cover.
3. Remove fuel hose using Quick Connector Release J-45488. Refer to EM-17
.
• Do not twist or kink fuel hose because it is plastic hose.
• Do not remove fuel hose from quick connector.
• Keep fuel hose connections clean.
SEF214Y
BBIA0380E

EC-120
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
*: Leaving cooling fan OFF with CONSULT-II while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to EC-49, "Emission-related Diagnostic Information".
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION• Engine: Return to the original
trouble condition
• Change the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.• Harness and connectors
• Fuel injector
• Air fuel ratio (A/F) sensor 1
IGNITION TIM-
ING• Engine: Return to the original
trouble condition
• Timing light: Set
• Retard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.• Perform Idle Air Volume Learning.
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-II.Engine runs rough or dies.• Harness and connectors
• Compression
• Fuel injector
• Power transistor
•Spark plug
• Ignition coil
COOLING FAN*• Ignition switch: ON
• Turn the cooling fan HI and OFF
using CONSULT-II.Cooling fan moves and stops.• Harness and connectors
• Cooling fan motor
• IPDM E/R
ENG COOLANT
TEMP• Engine: Return to the original
trouble condition
• Change the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.• Harness and connectors
• Engine coolant temperature sen-
sor
• Fuel injector
FUEL PUMP RE-
LAY• Ignition switch: ON
(Engine stopped)
• Turn the fuel pump relay ON and
OFF using CONSULT-II and lis-
ten to operating sound.Fuel pump relay makes the operat-
ing sound.• Harness and connectors
•Fuel pump relay
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-II.Engine speed changes according to
the opening percent.• Harness and connectors
• Solenoid valve
FUEL/T TEMP
SEN• Change the fuel tank temperature using CONSULT-II.
VENT CON-
TROL/V• Ignition switch: ON
(Engine stopped)
• Turn solenoid valve ON and OFF
with the CONSULT-II and listen to
operating sound.Solenoid valve makes an operating
sound.• Harness and connectors
• Solenoid valve
V/T ASSIGN AN-
GLE• Engine: Return to the original
trouble condition
• Change intake valve timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.• Harness and connectors
• Intake valve timing control sole-
noid valve
ALTERNATOR
DUTY•Engine: Idle
• Change duty ratio using CON-
SULT-II.Battery voltage changes.• Harness and connectors
• IPDM E/R
•Alternator

TROUBLE DIAGNOSIS
EC-121
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*: DTC P1442 and P1456 does not apply to JA60 models but appears in DTC Work Support Mode screens.
REAL TIME DIAGNOSIS IN DATA MONITOR MODE (RECORDING VEHICLE DATA)
Description
CONSULT-II has two kinds of triggers and they can be selected by touching “SETTING” in “DATA MONITOR”
mode.
1. “AUTO TRIG” (Automatic trigger):
• The malfunction will be identified on the CONSULT-II screen in
real time.
In other words, DTC/1st trip DTC and malfunction item will be
displayed if the malfunction is detected by ECM.
At the moment a malfunction is detected by ECM, “MONITOR”
in “DATA MONITOR” screen is changed to “Recording Data ...
xx%” as shown in the figure, and the data after the malfunction
detection is recorded. Then when the percentage reached
100%, “REAL-TIME DIAG” screen is displayed. If “STOP” is
touched on the screen during “Recording Data ... xx%”,
“REAL-TIME DIAG” screen is also displayed.
The recording time after the malfunction detection and the
recording speed can be changed by “TRIGGER POINT” and
“Recording Speed”. Refer to CONSULT-II Operation Manual.
2. “MANU TRIG” (Manual trigger):
• DTC/1st trip DTC and malfunction item will not be displayed
automatically on CONSULT-II screen even though a malfunc-
tion is detected by ECM.
DATA MONITOR can be performed continuously even though
a malfunction is detected.
Operation
1. “AUTO TRIG”
• While trying to detect the DTC/1st trip DTC by performing the DTC Confirmation Procedure, be sure to
select to “DATA MONITOR (AUTO TRIG)” mode. You can confirm the malfunction at the moment it is
detected.
• While narrowing down the possible causes, CONSULT-II should be set in “DATA MONITOR (AUTO
TRIG)” mode, especially in case the incident is intermittent.
Test mode Test item Corresponding DTC No. Reference page
EVAPORATIVE
SYSTEMPURG FLOW P0441 P0441EC-354
EVP SML LEAK P0442/P1442*P0442EC-359P0455EC-408
EVP V/S LEAK P0456/P1456* P0456EC-415
PURG VOL CN/V P1444 P0443EC-366
A/F SEN1A/F SEN1 (B1) P1276 P0130EC-225A/F SEN1 (B1) P1278/P1279 P0133EC-250
A/F SEN1 (B2) P1286 P0150EC-225
A/F SEN1 (B2) P1288/P1289 P0153EC-250
HO2S2HO2S2 (B1) P0139 P0139EC-282
HO2S2 (B1) P1146 P0138EC-270
HO2S2 (B1) P1147 P0137EC-260
HO2S2 (B2) P0159 P0159EC-282
HO2S2 (B2) P1166 P0158EC-270
HO2S2 (B2) P1167 P0157EC-260
SEF705Y
SEF707X

DTC P0125 ECT SENSOR
EC-217
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DTC P0125 ECT SENSOR
Component DescriptionINFOID:0000000003531719
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-205
.
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The electrical resistance of the ther-
mistor decreases as temperature increases.

*: This data is reference value and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000003531720
DTC Confirmation ProcedureINFOID:0000000003531721
CAUTION:
Be careful not to overheat engine.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Check that “COOLAN TEMP/S” is above 31°C (88°F).
If it is above 31°C (88°F), the test result will be OK.
If it is below 31°C (88°F), go to following step.
SEF594K
Engine coolant temperature
°C (°F)Voltage* V Resistance kΩ
–10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0125
0125Insufficient engine coolant
temperature for closed loop
fuel control• Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.
• Engine coolant temperature is insufficient for
closed loop fuel control.• Harness or connectors
(High resistance in the circuit)
• Engine coolant temperature sensor
•Thermostat

DTC P0130, P0150 A/F SENSOR 1
EC-227
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8. Make sure that “TESTING” changes to “COMPLETED”.
If “TESTING” changed to “OUT OF CONDITION”, retry from
step 6.
9. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULT”.
If “NG” is displayed, go to EC-231, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000003531740
PROCEDURE FOR MALFUNCTION B
Use this procedure to check the overall function of the A/F sensor 1 circuit. During this check, a 1st trip DTC
might not be confirmed.
With GST
1. Start engine and warm it up to normal operating temperature.
2. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in the suitable gear position.
3. Set shift lever to D position, then release the accelerator pedal fully until the vehicle speed decreases to
50 km/h (30 MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
4. Repeat steps 2 and 3 for five times.
5. Stop the vehicle and turn ignition switch OFF.
6. Wait at least 10 seconds and restart engine.
7. Repeat steps 2 and 3 for five times.
8. Stop the vehicle and connect GST to the vehicle.
9. Make sure that no 1st trip DTC is displayed.
If the 1st trip DTC is displayed, go to EC-231, "
Diagnosis Procedure".
SEF578Z