2011 INFINITI QX56 ECO mode

U1000 CAN COMM CIRCUITDLN-91
< DTC/CIRCUIT DIAGNOSIS > [TRANSFER: ATX90A]
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U1000 CAN COMM CIRCUIT
DescriptionINFOID:0000000006222300
CAN (Controller Area Network) is a serial communication li ne 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 communicate data but selectively reads required data only.
DTC LogicINFOID:0000000006222301
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC REPRODUCTION PROCEDURE
With CONSULT-III
1. Turn the ignition switch OFF to ON.
2. Perform self-diagnosis for “ALL MODE AWD/4WD”.
Is DTC
“U1000” detected?
YES >> Proceed to diagnosis procedure. Refer to DLN-91, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006222302
1.PERFORM SELF-DIAGNOSIS
With CONSULT-III
Perform self-diagnosis for “ALL MODE AWD/4WD”.
Is DTC
“U1000” detected?
YES >> Proceed to LAN-18, "Trouble Diagnosis Flow Chart".
NO >> INSPECTION END
DTC Display item Malfunction detected condition Possible cause
U1000 CAN COMM CIRCUIT Transfer control unit is not transmitting/
receiving CAN communication signal for
2 seconds or more. CAN communication error
 Malfunction of transfer control unit
Revision: 2010 May2011 QX56

EC-8
P2A00, P2A03 A/F SENSOR 1 .......................487
DTC Logic ............................................................ ..487
Diagnosis Procedure .............................................487
ASCD BRAKE SWITCH ................................. .490
Component Function Check ................................ ..490
Diagnosis Procedure .............................................490
Component Inspection (ASCD Brake Switch) .......491
ASCD INDICATOR ..........................................492
Component Function Check ................................ ..492
Diagnosis Procedure .............................................492
ELECTRICAL LOAD SIGNAL .........................493
Description ........................................................... ..493
Component Function Check ..................................493
Diagnosis Procedure .............................................493
ELECTRICALLY-CONTROLLED COOLING
FAN COUPLING ..............................................
495
Component Function Check ................................ ..495
Diagnosis Procedure .............................................495
FUEL INJECTOR .............................................498
Component Function Check ................................ ..498
Diagnosis Procedure .............................................498
Component Inspection ...........................................499
HIGH PRESSURE FUEL PUMP ......................501
Component Function Check ................................ ..501
Diagnosis Procedure .............................................501
Component Inspection ...........................................502
ICC BRAKE SWITCH ......................................503
Component Function Check ................................ ..503
Diagnosis Procedure .............................................503
Component Inspection (ICC Brake Switch) ...........505
IGNITION SIGNAL ...........................................506
Component Function Check ................................ ..506
Diagnosis Procedure .............................................506
Component Inspection (Ignition Coil with Power
Transistor) .............................................................
509
Component Inspection (Condenser) ......................510
INFORMATION DISPLAY (ASCD) ..................511
Component Function Check ................................ ..511
Diagnosis Procedure .............................................511
LOW PRESSURE FUEL PUMP ......................512
Component Function Check ................................ ..512
Diagnosis Procedure .............................................512
Component Inspection (Low Pressure Fuel Pump)
..
513
Component Inspection (FPCM) .............................514
MALFUNCTION INDICATOR LAMP ...............515
Component Function Check ................................ ..515
Diagnosis Procedure .............................................515
ON BOARD REFUELING VAPOR RECOV-
ERY (ORVR) .....................................................
516
Component Function Check ................................ .516
Diagnosis Procedure .............................................516
Component Inspection (EVAP Vapor Cut Valve) . .518
REFRIGERANT PRESSURE SENSOR ......... ..520
Component Function Check ................................ .520
Diagnosis Procedure .............................................520
SNOW MODE SWITCH ....................................522
Description ........................................................... .522
Component Function Check .................................522
Diagnosis Procedure .............................................522
Component Inspection ..........................................523
SYMPTOM DIAGNOSIS ...........................524
ENGINE CONTROL SYSTEM SYMPTOMS .. ..524
Symptom Table .................................................... .524
NORMAL OPERATING CONDITION ...............529
Description ........................................................... .529
PERIODIC MAINTENANCE ......................530
IDLE SPEED .......................... ...........................530
Inspection ............................................................. .530
IGNITION TIMING .............................................531
Inspection ............................................................. .531
EVAP LEAK CHECK ........................................532
Inspection ............................................................. .532
POSITIVE CRANKCASE VENTILATION .........534
Inspection ............................................................. .534
REMOVAL AND INSTALLATION .............535
ECM ................................................................ ..535
Removal and Installation ...................................... .535
VVEL CONTROL MODULE .............................536
Removal and Installation ...................................... .536
FUEL PUMP CONTROL MODULE (FPCM) ....537
Removal and Installation ...................................... .537
SERVICE DATA AND SPECIFICATIONS
(SDS) ........ .................................................
538
SERVICE DATA AND SPECIFICATIONS
(SDS) .............................................................. ..
538
Idle Speed ............................................................ .538
Ignition Timing .......................................................538
Calculated Load Value ..........................................538
Mass Air Flow Sensor ...........................................538
Revision: 2010 May2011 QX56

EC-52
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS DESCRIPTION
DIAGNOSIS DESCRIPTION : 1st Trip Detect
ion Logic and Two Trip Detection Logic
INFOID:0000000006217722
When a malfunction is detected for the first time, 1st tr ip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MIL will not illuminate at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MIL illuminates. The MIL illu minates at the same time when the DTC is stored.
<2nd trip> The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is per-
formed during vehicle operation. Specific on board diagnos tic items will cause the ECM to illuminate or blink
the MIL, and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
×: Applicable —: Not applicable
DIAGNOSIS DESCRIPTION : DT C and Freeze Frame DataINFOID:0000000006217723
DTC AND 1ST TRIP DTC
The 1st trip DTC (whose number is the same as the DT C number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously , and the 1st trip DTC did not recur, the 1st trip DTC
will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is saved in the ECM memory. The MIL will not
light up (two trip detection logic). If the same malfunc tion is not detected in the 2nd trip (meeting the required
driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same malfunction is detected in the
2nd trip, both the 1st trip DTC and DTC are saved in the ECM memory and the MIL lights up. In other words,
the DTC is stored in the ECM memory and the MIL light s up when the same malfunction occurs in two consec-
utive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed between the 1st and 2nd
trips, only the 1st trip DTC will continue to be stored. Fo r malfunctions that blink or light up the MIL during the
1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
For malfunctions in which 1st trip DTCs are displayed, refer to EC-98, "
DTC Index". These items are required
by legal regulations to continuous ly monitor the system/component. In addi tion, the items monitored non-con-
tinuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979/ ISO 15031-5. 1st trip DTC detection occurs without illu-
minating the MIL and therefore does not warn the driver of a malfunction.
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-135, "
Work Flow". Then perform DTC Confirma-
tion Procedure or Component Function Check to try to duplicate the malfunction. If the malfunction is dupli-
cated, the item requires repair.
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 ca lled freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-III screen.
Items MIL DTC 1st trip DTC
1st trip 2nd trip 1st trip
displaying 2nd trip
displaying 1st trip
displaying 2nd trip
displaying
Blinking Illuminate Blinking Illuminate
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected ×
——— — — ×—
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected ——
×—— ×——
One trip detection diagnoses (Re-
fer to EC-98, "
DTC Index".) —
×—— ×———
Except above — — — ×— ×× —
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-53
< SYSTEM DESCRIPTION > [VK56VD]
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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 (Priority: 2) was detected and the freeze frame data was saved 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
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 dat a (along with the DTCs) are cleared when the ECM mem-
ory is erased.
DIAGNOSIS DESCRIPTION : Counter SystemINFOID:0000000006217724
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 consec utive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MIL will come on.
 The MIL will turn OFF after the vehicle is driven 3 ti mes (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 v ehicle 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-
tion System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driving pattern
C) without the same malfunction recurring. The “TIM E” in “SELF-DIAGNOSTIC RESULTS” mode of CON-
SULT-III will count the number of times the vehicle is driven.
 The 1st trip DTC is not displayed when the se lf-diagnosis results in OK for the 2nd trip.
COUNTER SYSTEM CHART
For details about patterns B and C under “Fuel Inject ion System” and “Misfire”, see “EXPLANATION FOR
DRIVING PATTERNS FOR “MISFIRE ”, “FUEL INJECTION SYS-
TEM”.
For details about patterns A and B under Other, see “EXPLANATION FOR DRIVING PATTERNS FOR “MIS-
FIRE ”, “FUEL INJECTION SYSTEM”.
 *1: Clear timing is at the moment OK is detected.
 *2: Clear timing is when the same malfunction is detected in the 2nd trip.
Relationship Between MIL, DTC, 1st Trip DTC and Dr iving Patterns for “Misfire terioration>”, “Fuel Injection System”
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items
3 1st trip freeze frame data
Items Fuel Injection System Misfire Other
MIL (turns OFF) 3 (pattern B) 3 (pattern B) 3 (pattern B)
DTC, Freeze Frame Data (no display) 80 (p attern C) 80 (pattern C) 40 (pattern A)
1st Trip DTC (clear) 1 (pattern C), *1 1 (pattern C), *1 1 (pattern B)
1st Trip Freeze Frame Data (clear) *1, *2 *1, *2 1 (pattern B)
Revision: 2010 May2011 QX56

EC-60
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS DESCRIPTION : Malf unction Indicator Lamp (MIL)
INFOID:0000000006217727
DESCRIPTION
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON with-
out the engine running. This is a bulb check.
If the MIL does not light up, refer to EC-515, "
Component Func-
tion Check".
2. When the engine is started, the MIL should go off. If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
On Board Diagn osis FunctionINFOID:0000000006217728
ON BOARD DIAGNOSIS ITEM
The on board diagnostic system has the following functions.
BLUB CHECK MODE
Description
This function allows damage inspection in the MIL bulb (blown, open circuit, etc.).
Operation Procedure
1. Turn ignition switch ON.
2. The MIL on the instrument panel should stay ON.
If it remains OFF, check MIL circuit. Refer to EC-515, "
Diagnosis Procedure".
SRT STATUS MODE
Description
This function allows to read if ECM has completed t he self-diagnoses of major emission control systems and
components. For SRT, refer to EC-58, "
DIAGNOSIS DESCRIPTION : Syst em Readiness Test (SRT) Code".
Operation Procedure
1. Turn ignition switch ON and wait 20 seconds.
2. SRT status is indicated as shown blow.
 ECM continues to illuminate MIL if all SRT codes are set.
SEF217U
Diagnostic test mode Function
Bulb check MIL can be checked.
SRT status ECM can read if SRT codes are set.
Malfunction warning If ECM detects a malfunction, it illuminates or blinks MIL to inform the driver that a malfunction has been detected.
Self-diagnostic results DTCs or 1st trip DTCs stored in ECM can be read.
Accelerator pedal released po-
sition learning ECM can learn the accelerator pedal released position. Refer to
EC-146, "
Description".
Throttle valve closed position
learning ECM can learn the throttle valve closed position. Refer to
EC-147, "
Description".
Idle air volume learning ECM can learn the idle air volume. Refer to EC-148, "
Description".
VVEL control sh aft position
sensor adjustment The initial position of the VVEL control shaft position sensor can be adjusted. Refer to
EC-150, "
De-
scription".
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-61
< SYSTEM DESCRIPTION > [VK56VD]
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 ECM blinks MIL for about 10 seconds if all SRT codes are not set.
MALFUNCTION WARNING MODE
Description
In this function ECM turns on or blinks MIL when it det
ects a malfunction in the emission control system com-
ponents and/or the powertrain control components (which affe ct vehicle emissions) to inform the driver that a
malfunction has been detected.
Operation Procedure
1. Turn ignition switch ON.
2. Check that MIL illuminates. If it remains OFF, check MIL circuit. Refer to EC-515, "
Diagnosis Procedure".
3. Start engine and let it idle.  For two trip detection logic diagnoses, ECM turns on MIL when it detects the same malfunction twice in
the two consecutive driving cycles.
 For 1st trip detection logic diagnoses, ECM turns on MIL when it detects a malfunction in one driving cycle.
 ECM blinks MIL when it detects a malfunction t hat may damage the three way catalyst (misfire).
SELF-DIAGNOSTIC RESULTS MODE
Description
This function allows to indicate DTCs or 1st trip DTCs stored in ECM according to the number of times MIL is
blinking.
How to Set Self-diagnostic Results Mode
NOTE:
 It is better to count the time accurately with a clock.
 It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a mal-
function.
 After ignition switch is turned off, ECM is a lways released from the “Self-diagnostic results” mode.
1. Confirm that accelerator pedal is fully releas ed, turn ignition switch ON and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.  Fully depress the accelerator pedal.
 Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it depressed for approx. 10 seconds until the
MIL starts blinking.
NOTE:
Do not release the accelerator pedal for 10 seconds if MIL starts blinking during this period. This blinking
is displaying SRT status and is continued for another 10 seconds.
4. Fully release the accelerator pedal. ECM has entered to Self-diagnostic results mode.
JMBIA1515GB
Revision: 2010 May2011 QX56

EC-62
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
NOTE:
Wait until the same DTC (or 1st trip DTC)
appears to completely confirm all DTCs.
How to Read Self-diagnostic Results
The DTC and 1st trip DTC are indicated by the number of blinks of the MIL as shown below.
The DTC and 1st trip DTC are displayed at the same time. If the MIL does not illuminate in diagnostic test
mode I (Malfunction warning), all displayed items are 1s t trip DTCs. If only one code is displayed when the MIL
illuminates in “malfunction warning” mode, it is a DTC; if two or more codes are displayed, they may be either
DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These unidentified codes can be identified by
using the CONSULT-III 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 per the following.
The length of time the 1,000th-digit numeral flashes on and off is 1.2 seconds consisting of an ON (0.6-sec-
onds) - OFF (0.6-seconds) cycle.
The 100th-digit numeral and lower digit numerals consis t of a 0.3-seconds ON and 0.3-seconds OFF cycle.
A change from one digit numeral to another occurs at an inte rval 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-seconds OFF.
PBIB0092E
PBIB3005E
Number 0123456789ABCDEF
Flashes 10123456789111213141516
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-63
< SYSTEM DESCRIPTION > [VK56VD]
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In this way, all the detected malfunctions are classi
fied by their DTC numbers. The DTC 0000 refers to no mal-
function. Refer to EC-98, "
DTC Index".
How to Erase Self-diagnostic Results
By performing this procedure, ECM memory is erased and the following diagnostic information is erased as
well.
 Diagnostic trouble codes
 1st trip diagnostic trouble codes
 Freeze frame data
 1st trip freeze frame data
 System readiness test (SRT) codes
 Test values
NOTE:
Also, if a battery terminal is disconnected, ECM memory is erased and the diagnostic information as listed
above is erased. (The amount of time required for eras ing may vary from a few seconds to several hours.)
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON.
5. Set ECM in Self-diagnostic results.
6. The diagnostic information has been erased from the backup memory in the ECM. Fully depress the accelerator pedal and keep it depressed for more than 10 seconds.
7. Fully release the accelerator pedal, and confirm the DTC 0000 is displayed.
CONSULT-III FunctionINFOID:0000000006217729
FUNCTION
*: The following emission-related diagnostic information is cleared when the ECM memory is erased.
 Diagnostic trouble codes
 1st trip diagnostic trouble codes
 Freeze frame data
 1st trip freeze frame data
 System readiness test (SRT) codes
Test values
WORK SUPPORT MODE
Work Item
Diagnostic test mode Function
Work support This mode enables a technician to adjust some devices faster and more accurately by following the in-
dications on the CONSULT-III unit.
Self diagnostic result Self-diagnostic results such as 1st trip DTC, DTCs and 1st trip freeze frame data or freeze frame data
can be read and erased quickly.*
Data monitor Input/Output data in the ECM can be read.
Active test Diagnostic Test Mode in which CONSULT-III drives some actuators apart from the ECMs and also shifts
some parameters in
a specified range.
DTC & SRT confirmation The status of system monitoring tests and the self-diagnosis status/results can be confirmed.
Function test This mode is used to inform customers when the vehicle requires periodic maintenance.
ECU identification ECM part number can be read.
Revision: 2010 May2011 QX56