EC-14Revision: November 2009
INDEX FOR DTC
2006 QX56
FUEL SYS-RICH-B2P01750175 EC-299
HLR/C SOL/CIRC P17671767 AT-151
HLR/C SOL FNCTN P17691769 AT-153
HO2S2 (B1) P01370137 EC-253
HO2S2 (B1) P01380138 EC-264
HO2S2 (B1) P01390139 EC-277
HO2S2 (B2) P01570157 EC-253
HO2S2 (B2) P01580158 EC-264
HO2S2 (B2) P01590159 EC-277
HO2S2 HTR (B1) P00370037 EC-163
HO2S2 HTR (B1) P00380038 EC-163
HO2S2 HTR (B2) P00570057 EC-163
HO2S2 HTR (B2) P00580058 EC-163
I/C SOLENOID/CIRC P17521752 AT-139
I/C SOLENOID FNCTN P17541754 AT-141
IAT SEN/CIRCUIT P01120112 EC-188
IAT SEN/CIRCUIT P01130113 EC-188
IAT SENSOR P01270127 EC-208
ISC SYSTEM P05060506 EC-444
ISC SYSTEM P05070507 EC-446
KNOCK SEN/CIRC-B1 P03270327 EC-335
KNOCK SEN/CIRC-B1 P03280328 EC-335
KNOCK SEN/CIRC-B2 P03320332 EC-335
KNOCK SEN/CIRC-B2 P03330333 EC-335
L/PRESS SOL/CIRC P07450745 AT-122
LC/B SOLENOID/CIRC P17721772 AT-155
LC/B SOLENOID FNCT P17741774 AT-157
MAF SEN/CIRCUIT P01010101 EC-171
MAF SEN/CIRCUIT P01020102 EC-180
MAF SEN/CIRCUIT P01030103 EC-180
MULTI CYL MISFIRE P03000300 EC-327
NATS MALFUNCTION P1610 - P16151610 - 1615 BL-137
NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED. P0000
0000 —
P-N POS SW/CIRCUIT P08500850 EC-465
PNP SW/CIRC P07050705 AT-105
PURG VOLUME CONT/V P04430443 EC-373
PURG VOLUME CONT/V P04440444 EC-381
PURG VOLUME CONT/V P04450445 EC-381
PW ST P SEN/CIRC P05500550 EC-448
SENSOR POWER/CIRC P06430643 EC-460
TCC SOLENOID/CIRC P07400740 AT- 11 8
Items
(CONSULT-II screen terms) DTC*
1
Reference page
CONSULT-II
GST*
2ECM*3
INDEX FOR DTCEC-15
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*1: 1st trip DTC No. is the same as DTC No.
*2: This number is prescribed by SAE J2012.
*3: In Diagnostic Test Mode II (Self-diagnostic results), this number is controlled by NISSAN.
*4: The troubleshooting for this DTC needs CONSULT-II.
*5: When the fail-safe operations for both self-diagnoses occur, the MIL illuminates.
*6: 2WD models
*7: Models with ICCTCM
P07000700 AT-104
TCS C/U FUNCTN P12111211 EC-471
TCS/CIRC P12121212 EC-472
THERMSTAT FNCTN P01280128 EC-211
TP SEN 1/CIRC P02220222 EC-320
TP SEN 1/CIRC P02230223 EC-320
TP SEN 2/CIRC P01220122 EC-198
TP SEN 2/CIRC P01230123 EC-198
TP SENSOR P21352135 EC-560
TURBINE REV S/CIRC P07170717 AT-109
TW CATALYST SYS-B1 P04200420 EC-354
TW CATALYST SYS-B2 P04300430 EC-354
VEH SPD SEN/CIR AT*5P07200720 AT- 111
VEH SPEED SEN/CIRC*5P05000500 EC-442
VENT CONTROL VALVE P04470447 EC-388
VENT CONTROL VALVE P04480448 EC-395
Items
(CONSULT-II screen terms) DTC*
1
Reference page
CONSULT-II
GST*
2ECM*3
EC-16Revision: November 2009
PRECAUTIONS
2006 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
UBS00KZ0
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER ”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WARNING:
To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.
Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.
Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
On Board Diagnostic (OBD) System of Engine and A/TUBS00KZ1
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
Be sure to turn the ignition switch OFF and disconnect the negative battery cable before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves,
etc. will cause the MIL to light up.
Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
Certain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to PG-68, "
HAR-
NESS CONNECTOR" .
Be sure to route and secure the harnesses properly after work. The interference of the harness
with a bracket, etc. may cause the MIL to light up due to the short circuit.
Be sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the EVAP system or fuel injection system,
etc.
Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
PrecautionUBS00KZ2
Always use a 12 volt battery as power source.
Do not attempt to disconnect battery cables while engine is
running.
Before connecting or disconnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect negative
battery cable. Failure to do so may damage the ECM
because battery voltage is applied to ECM even if ignition
switch is turned OFF.
Before removing parts, turn ignition switch OFF and then
disconnect negative battery cable.
SEF289H
PRECAUTIONSEC-17
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Do not disassemble ECM.
If a battery cable is disconnected, the memory will return to
the ECM value.
The ECM will now start to self-control at its initial value.
Engine operation can vary slightly when the terminal is dis-
connected. However, this is not an indication of a malfunc-
tion. Do not replace parts because of a slight variation.
If the battery is disconnected, the following emission-
related diagnostic information will be lost within 24 hours.
–Diagnostic trouble codes
–1st trip diagnostic trouble codes
–Freeze frame data
–1st trip freeze frame data
–System readiness test (SRT) codes
–Test values
When connecting ECM harness connector, fasten it
securely with a lever as far as it will go as shown in the fig-
ure.
When connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.
Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge)
voltage to develop in coil and condenser, thus resulting in
damage to ICs.
Keep engine control system harness at least 10 cm (4 in)
away from adjacent harness, to prevent engine control sys-
tem malfunctions due to receiving external noise, degraded
operation of ICs, etc.
Keep engine control system parts and harness dry.
Before replacing ECM, perform ECM Terminals and Refer-
ence Value inspection and make sure ECM functions prop-
erly. Refer to EC-105, "
ECM Terminals and Reference Value"
.
Handle mass air flow sensor carefully to avoid damage.
Do not disassemble mass air flow sensor.
Do not clean mass air flow sensor with any type of deter-
gent.
Do not disassemble electric throttle control actuator.
Even a slight leak in the air intake system can cause seri-
ous incidents.
Do not shock or jar the camshaft position sensor (PHASE), crankshaft position sensor (POS).
PBIB1164E
BBIA0387E
PBIB0090E
MEF040D
EC-20Revision: November 2009
PREPARATION
2006 QX56
PREPARATIONPFP:00002
Special Service ToolsUBS00KZ4
The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.Tool number
(Kent-Moore No.)
Tool name Description
EG17650301
(J-33984-A)
Radiator cap tester
adapter Adapting radiator cap tester to radiator cap and ra-
diator filler neck
a: 28 (1.10) dia.
b: 31.4 (1.236) dia.
c: 41.3 (1.626) dia.
Unit: mm (in)
KV10117100
(J-36471-A)
Heated oxygen sensor
wrench Loosening or tightening heated oxygen sensors
with 22 mm (0.87 in) hexagon nut
KV10114400
(J-38365)
Heated oxygen sensor
wrench Loosening or tightening heated oxygen sensors
a: 22 mm (0.87 in)
(J-44626)
Air fuel ratio (A/F) sen-
sor wrench Loosening or tightening air fuel ratio (A/F) sensor 1
(J-44321)
Fuel pressure gauge
kit Checking fuel pressure
(J-44321-6)
Fuel pressure adapter Connecting fuel pressure gauge to quick connec-
tor type fuel lines.
(J-45488)
Quick connector re-
lease Remove fuel tube quick connectors in engine
room.
S-NT564
S-NT379
S-NT636
LEM054
LEC642
LBIA0376E
PBIC0198E
EC-22Revision: November 2009
PREPARATION
2006 QX56
Commercial Service ToolsUBS00KZ5
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
Oxygen sensor thread
cleaner
i.e.: (J-43897-18)
(J-43897-12) Reconditioning the exhaust system threads before
installing a new oxygen sensor. Use with anti-
seize lubricant shown below.
a: 18 mm diameter with pitch 1.5 mm for Zirco-
nia Oxygen Sensor
b: 12 mm diameter with pitch 1.25 mm for Tita-
nia Oxygen Sensor
Anti-seize lubricant
i.e.: (Permatex
TM
133AR or equivalent
meeting MIL specifica-
tion MIL-A-907) Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
S-NT703
S-NT704
S-NT815
S-NT705
AEM488
S-NT779
EC-24Revision: November 2009
ENGINE CONTROL SYSTEM
2006 QX56
Multiport Fuel Injection (MFI) SystemUBS00KZ7
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*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 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 ECMECM functionActuator
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
Air fuel ratio (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 sensorPower steering operation
Heated oxygen sensor 2 Density of oxygen in exhaust gas*
1
ABS actuator and electric unit (control unit)VDC/TCS operation command*2
Air conditioner switch
Air conditioner operation*2
Wheel sensorVehicle speed*2
ENGINE CONTROL SYSTEMEC-25
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MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce CO, HC and NOx emissions. This system uses air
fuel ratio (A/F) sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about air
fuel ratio (A/F) sensor 1, refer to EC-213, "
DTC P0130, P0150 A/F SENSOR 1" . This maintains the mixture
ratio within the range of stoichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst (manifold). Even if the switching
characteristics of air fuel ratio (A/F) sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal
from heated oxygen sensor 2.
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
Deceleration and acceleration
High-load, high-speed operation
Malfunction of A/F sensor 1 or its circuit
Insufficient activation of A/F sensor 1 at low engine coolant temperature
High engine coolant temperature
During warm-up
After shifting from N to D
When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim ” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim ” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long term fuel trim ” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
PBIB3020E