2009 INFINITI QX56 OBD port

EC-1
ENGINE
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SECTION EC
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CONTENTS
ENGINE CONTROL SYSTEM
VK56DE
BASIC INSPECTION ....... .............................
8
DIAGNOSIS AND REPAIR WORKFLOW ..... .....8
Trouble Diagnosis Introduction ........................... ......8
INSPECTION AND ADJUSTMENT ....................13
Basic Inspection .................................................. ....13
Idle Speed and Ignition Timing Check ....................17
Procedure After Replacing ECM .............................17
VIN Registration ......................................................17
Accelerator Pedal Released Position Learning .......18
Throttle Valve Closed Position Learning .................18
Idle Air Volume Learning .........................................18
FUNCTION DIAGNOSIS ..............................21
ENGINE CONTROL SYSTEM ........................ ....21
System Diagram .................................................. ....21
Engine Control Component Parts Location .............22
MULTIPORT FUEL INJECTION SYSTEM .........28
System Description ............................................. ....28
ELECTRIC IGNITION SYSTEM ..................... ....31
System Description ............................................. ....31
AIR CONDITIONING CUT CONTROL ...............32
Input/Output Signal Chart .................................... ....32
System Description .................................................32
AUTOMATIC SPEED CONTROL DEVICE
(ASCD) ...............................................................
33
System Description ............................................. ....33
Component Description ...........................................34
CAN COMMUNICATION ....................................35
System Description ............................................. ....35
COOLING FAN CONTROL ................................36
Description .......................................................... ....36
EVAPORATIVE EMISSION SYSTEM ...............37
Description ........................................................... ....37
INTAKE VALVE TIMING CONTROL ................40
Description ...............................................................40
ON BOARD DIAGNOSTIC (OBD) SYSTEM ....41
Introduction ..............................................................41
Two Trip Detection Logic .........................................41
Emission-related Diagnostic Information .................42
Malfunction Indicator Lamp (MIL) ............................55
OBD System Operation Chart .................................58
CONSULT-III Function (ENGINE) ...........................63
Generic Scan Tool (GST) Function .........................72
COMPONENT DIAGNOSIS .........................74
TROUBLE DIAGNOSIS - SPECIFICATION
VALUE ...............................................................
74
Description ........................................................... ....74
Testing Condition .....................................................74
Inspection Procedure ...............................................74
Diagnosis Procedure ...............................................75
POWER SUPPLY AND GROUND CIRCUIT ....82
Diagnosis Procedure ...............................................82
Ground Inspection ...................................................85
U1000, U1001 CAN COMM CIRCUIT ...............86
Description ...............................................................86
On Board Diagnosis Logic .......................................86
DTC Confirmation Procedure ..................................86
Diagnosis Procedure ...............................................86
P0011, P0021 IVT CONTROL ...........................87
On Board Diagnosis Logic .......................................87
DTC Confirmation Procedure ..................................87
Diagnosis Procedure ...............................................88
Component Inspection .............................................92
P0031, P0032, P0051, P0052 A/F SENSOR 1
HEATER ............................................................
94
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ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-43
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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
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. Procedures for clearing the ECM me mory 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 & Ma intenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has comple ted 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 inspec tion 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 syste m. 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.
NOTE:
The SRT will also indicate “INCMP” if the self-diagnosis memory is erased for any reason or if the ECM mem-
ory power supply is interrupted for several hours.
If, during the state emissions inspection, the SRT indica tes “CMPLT” for all test items, the inspector will con-
tinue with the emissions test. However, if the SRT i ndicates “INCMP” for one or more of the SRT items the
vehicle is returned to the customer untested.
NOTE:
If MIL is ON during the state emissi ons inspection, the vehicle is also returned to the customer untested even
though the SRT indicates “CMPLT” for all test items. T herefore, it is important to check SRT (“CMPLT”) and
DTC (No DTCs) before the inspection.
SRT Item
The table below shows required self-diagnostic items to set the SRT to “CMPLT”.
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
SRT item
(CONSULT-III indication) Performance
Priority* Required self-diagnostic items to set the SRT to “CMPLT”
Corresponding
DTC No.
CATALYST 2 Three way catalyst function P0420, P0430
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 The A counter will be cleared when the malfunc
tion is detected regardless of (1) - (4).
 The A counter will be counted up when (1) - (4) are satisfied without the same malfunction.
 The DTC will not be displayed after the A counter reaches 40.

Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
 The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
 The B counter will be counted up when driving pattern B is satisfied without any malfunctions.
 The MIL will go off when the B counter reac hes 3 (*2 in OBD SYSTEM OPERATION CHART).
CONSULT-III Function (ENGINE)INFOID:0000000003771318
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
ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
AEC574
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 results 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.
Function test This mode is used to inform customers when their vehicle condition requires periodic maintenance.
DTC & SRT confirmation The status of system monitoring tests and the self-diagnosis status/result can be confirmed.
ECU Identification ECM part number can be read.
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EC-64
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
ItemDIAGNOSTIC TEST MODE
WORK SUP-
PORT SELF-DIAGNOSTIC
RESULTS DATA
MONI-
TOR ACTIVE
TEST DTC & SRT
CONFIRMATION
DTC*1 FREEZE
FRAME
DATA*2 SRT
STATUS DTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS) ×××
Camshaft position sensor (PHASE) ×××
Mass air flow sensor ××
Engine coolant temperature sensor ××××
Air fuel ratio (A/F) sensor 1 ××××
Heated oxygen sensor 2 ××××
Wheel sensor ×××
Accelerator pedal position sensor ××
Throttle position sensor ×××
Fuel tank temperature sensor ×××
EVAP control system pressure sen-
sor ××
Intake air temperature sensor ×××
Knock sensor ×
Refrigerant pressure sensor ×
Closed throttle position switch (ac-
celerator pedal position sensor sig-
nal) ×
Air conditioner switch ×
Transmission range signal ××
Stop lamp switch ××
Power steering pressure sensor ××
Battery voltage ×
Load signal ×
Intake valve timing control position
sensor ××
Fuel level sensor ××
Battery current sensor ××
ICC steering switch ××
ASCD steering switch ××
ICC brake switch ××
ASCD brake switch ××
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X: Applicable
*1: This item includes 1st trip DTCs.
*2: This mode includes 1st trip freeze frame data or freeze frame data. The items appear on CONSULT-III screen in freeze frame
data
mode only if a 1st trip DTC or DTC is detected. For details, refer to "Freeze Frame Data and 1st Trip Freeze Frame Data".
*3: Always “CMPLT ” is displayed.
WORK SUPPORT MODE
Work Item
ENGINE CONTROL COMPONENT PARTS
OUTPUT
Fuel injector ××
Power transistor (Ignition timing) ××
Throttle contro l motor relay ××
Throttle control motor ×
EVAP canister purge volume con-
trol solenoid valve ××××
Air conditioner relay ×
Fuel pump relay ×××
Cooling fan relay ×××
Air fuel ratio (A/F) sensor 1 heater ×××*3
Heated oxygen sensor 2 heater ×××*3
EVAP canister vent control valve ×× ××
Intake valve timing control solenoid
valve ×××
Alternator ××
Calculated load value ××
Item
DIAGNOSTIC TEST MODE
WORK SUP-
PORT SELF-DIAGNOSTIC
RESULTS DATA
MONI- TOR ACTIVE
TEST DTC & SRT
CONFIRMATION
DTC*1 FREEZE
FRAME
DATA*2 SRT
STATUS DTC
WORK SUP-
PORT
WORK ITEM CONDITION USAGE
FUEL PRESSURE RELEASE  FUEL PUMP WILL STOP BY TOUCHING “START” DUR- ING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS. When releasing fuel pressure from
fuel line
IDLE AIR VOL LEARN  THE IDLE AIR VOLUME THAT KEEPS THE ENGINE WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM. When learning the idle air volume
SELF-LEARNING CONT  THE COEFFICI ENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL COEF-
FICIENT. When clearing the coefficient of
self-learning control value
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to
EC-456, "DTC Index".
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-III. 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-III. 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-III. 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-III. 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-III. 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-III 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-III. Engine speed changes according to
the opening percent.
 Harness and connectors
 Solenoid valve
FUEL/T TEMP
SEN  Change the fuel tank temperature using CONSULT-III.
VENT CON-
TROL/V  Ignition switch: ON
(Engine stopped)
 Turn solenoid valve ON and OFF with the CONSULT-III 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-III. 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-III. Battery voltage changes.  Harness and connectors
IPDM E/R
 Alternator
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EC-72
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
*: DTC P1442 and P1456 does not apply to JA60 models but appears in DTC Work Support Mode screens.
Generic Scan Tool (GST) FunctionINFOID:0000000003771319
DESCRIPTION
Generic Scan Tool (OBDII scan tool) complying with SAE J1978 has
8 different functions explained below.
ISO15765-4 is used as the protocol.
The name GST or Generic Scan Tool is used in this service manual.
FUNCTION
Test mode Test item Corresponding DTC No. Reference page
EVAPORATIVE
SYSTEM PURG FLOW P0441 P0441
EC-210
EVP SML LEAK P0442/P1442*P0442
EC-215P0455EC-250
EVP V/S LEAK P0456/P1456* P0456 EC-257
PURG VOL CN/V P1444 P0443EC-222
A/F SEN1A/F SEN1 (B1) P1276 P0130
EC-136A/F SEN1 (B1) P1278/P1279 P0133EC-146
A/F SEN1 (B2) P1286 P0150EC-136
A/F SEN1 (B2) P1288/P1289 P0153EC-146
HO2S2HO2S2 (B1) P0139 P0139
EC-164
HO2S2 (B1) P1146 P0138EC-157
HO2S2 (B1) P1147 P0137EC-152
HO2S2 (B2) P0159 P0159EC-164
HO2S2 (B2) P1166 P0158EC-157
HO2S2 (B2) P1167 P0157EC-152
SEF139P
Diagnostic test mode Function
Service $01 READINESS TESTS This diagnostic service gains access to current emission-related data values, including an-
alog inputs and outputs, digital inputs and outputs, and system status information.
Service $02 (FREEZE DATA) This diagnostic service gains access to emission-related data value which were stored by
ECM during the freeze frame. For details, refer to
EC-456, "DTC Index"
.
Service $03 DTCs This diagnostic service gains access to emission-related power train trouble codes which
were stored by ECM.
Service $04 CLEAR DIAG INFO This diagnostic service can clear all emission-related diagnostic information. This in-
cludes:
 Clear number of diagnostic trouble codes (Service $01)
 Clear diagnostic trouble codes (Service $03)
 Clear trouble code for freeze frame data (Service $01)
 Clear freeze frame data (Service $02)
 Reset status of system monitoring test (Service $01)
 Clear on board monitoring test results (Service $06 and $07)
Service $06 (ON BOARD TESTS) This diagnostic service accesses the results of on board diagnostic monitoring tests of
specific components/systems that are not continuously monitored.
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PREPARATIONEC-485
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Commercial Service ToolINFOID:0000000003771745
(J-45488)
Quick connector re-
lease
Remove fuel tube quick connectors in engine
room.
(J-23688)
Engine coolant refrac-
tometer Checking concentration of ethylene glycol in en-
gine coolant
Tool number
(Kent-Moore No.)
Tool name
Description
PBIC0198E
WBIA0539E
Tool name
(Kent-Moore No.)
Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD) Applying positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382) Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant tempera- ture sensor
S-NT703
S-NT704
S-NT815
S-NT705
Revision: December 20092009 QX56