engine INFINITI QX56 2006 Factory Service Manual

TROUBLE DIAGNOSISEC-83
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionUBS00L02
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output signals are proper and stable. At the
same time, it is important that there are no malfunctions such as vac-
uum leaks, fouled spark plugs, or other malfunctions with the engine.
It is much more difficult to diagnose an incident that occurs intermit-
tently rather than continuously. Most intermittent incidents are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the incidents. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the Work Flow on EC-84, "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A Diagnostic Worksheet like the example
on EC-88, "
Worksheet Sample" should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
MEF036D
SEF233G
SEF234G

TROUBLE DIAGNOSISEC-87
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
10. DETECT MALFUNCTIONING PART BY DIAGNOSTIC PROCEDURE
Inspect according to Diagnostic Procedure of the system.
NOTE:
The Diagnostic Procedure in EC section described based on open circuit inspection. A short circuit inspection
is also required for the circuit check in the Diagnostic Procedure. For details, refer to Circuit Inspection in GI-
28, "How to Perform Efficient Diagnosis for an Electrical Incident" .
Is malfunctioning part detected?
Ye s > > G O T O 11 .
No >> Monitor input data from related sensors or check voltage of related ECM terminals using CON- SULT-II. Refer to EC-105, "
ECM Terminals and Reference Value" , EC-129, "CONSULT-II Refer-
ence Value in Data Monitor" .
11 . REPAIR OR REPLACE THE MALFUNCTIONING PART
1. Repair or replace the malfunctioning part.
2. Reconnect parts or connectors disconnected during Diagnostic Procedure again after repair and replace- ment.
3. Check DTC. If DTC is displayed, erase it, refer to EC-61, "
HOW TO ERASE EMISSION-RELATED DIAG-
NOSTIC INFORMATION" .
>> GO TO 12.
12. FINAL CHECK
When DTC was detected in step 2, perform DTC Confirmation Procedure or Overall Function Check again,
and then make sure that the malfunction have been repaired securely.
When symptom was described from the customer, refer to confirmed symptom in step 3 or 4, and make sure
that the symptom is not detected.
OK or NG
NG (DTC*1 is detected)>>GO TO 10.
NG (Symptom remains)>>GO TO 6.
OK >> 1. Before returning the vehicle to the customer, make sure to erase unnecessary DTC*
1 in ECM
and TCM (Transmission Control Module). (Refer to EC-61, "
HOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATION" and AT- 3 8 , "OBD-II Diagnostic Trouble Code
(DTC)" .)
2. If the completion of SRT is needed, drive vehicle under the specific driving pattern. Refer to EC-
58, "Driving Pattern" .
3. INSPECTION END
*1: Include 1st trip DTC.
*2: Include 1st trip freeze frame data.
DIAGNOSTIC WORKSHEET
Description
There are many operating conditions that lead to the malfunction of
engine components. A good grasp of such conditions can make trou-
bleshooting faster and more accurate.
In general, each customer feels differently about a incident. It is
important to fully understand the symptoms or conditions for a cus-
tomer complaint.
Utilize a diagnostic worksheet like the one on the next page in order
to organize all the information for troubleshooting.
Some conditions may cause the MIL to come on steady or blink and
DTC to be detected. Examples:

Vehicle ran out of fuel, which caused the engine to misfire.

Fuel filler cap was left off or incorrectly screwed on, allowing fuel
to evaporate into the atmosphere.
SEF907L

TROUBLE DIAGNOSISEC-89
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
DTC Inspection Priority ChartUBS00L03
If some DTCs are displayed at the same time, perform 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-151, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC U1010 is displayed with other DTC, first perform the trouble diagnosis for DTC U1010. Refer
to EC-154, "
DTC U1010 CAN COMMUNICATION" .
Priority Detected items (DTC)
1

U1000 U1001 CAN communication line

U1010 CAN communication

P0101 P0102 P0103 Mass air flow sensor

P0112 P0113 P0127 Intake air temperature sensor

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 position sensor (PHASE)

P0460 P0461 P0462 P0463 Fuel level sensor

P0500 Vehicle speed sensor

P0605 ECM

P0643 Sensor power supply

P0705 Park/Neutral position (PNP) switch

P0850 Park/Neutral position (PNP) switch

P1610 - P1615 NATS

P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor

EC-90Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
2
P0031 P0032 P0051 P0052 Air fuel ratio (A/F) sensor 1 heater

P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater

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

P0700 P0710 P0717 P0720 P0740 P0744 P0745 P1730 P1752 P1754 P1757 P1759 P1762 P1764 P1767 P1769
P1772 P1774 A/T related sensors and solenoid valves

P1217 Engine over temperature (OVERHEAT)

P1805 Brake switch

P2100 P2103 P2118 Electric throttle control actuator

P2101 Electric throttle control function
3

P0171 P0172 P0174 P0175 Fuel injection system function

P0300 - P0308 Misfire

P0420 P0430 Three way catalyst function

P0442 P0455 P0456 EVAP control system

P0506 P0507 Idle speed control system

P1148 P1168 Closed loop control

P1211 TCS control unit

P1212 TCS communication line

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)

TROUBLE DIAGNOSISEC-91
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
Fail-safe ChartUBS00L04
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.

When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting up MIL when
there is malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engine control system malfunctions and MIL circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected and demands
the driver to repair the malfunction.
DTC No. Detected itemsEngine 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 time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or START 40
°C (104 °F)
More than approx. 4 minutes after
ignition ON or START 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 throttle control actuator (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

EC-92Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
Symptom Matrix ChartUBS00L05
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOMRefer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-604
Fuel pressure regulator system 334444444 4 EC-82
Injector circuit11232 22 2EC-598
Evaporative emission system 334444444 4 EC-32
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-45
Incorrect idle speed adjustment 1 1 1 1 1EC-71
Electric throttle control actuator 112332222 2 2 EC-528
,
EC-534
,
EC-540
,
EC-545
IgnitionIncorrect ignition timing adjustment 33111 11 1EC-71
Ignition circuit 11222 22 2EC-618
Main power supply and ground circuit 22333 33 23 EC-145
Mass air flow sensor circuit
1
12 2
222 2 EC-171,
EC-180
Engine coolant temperature sensor circuit
333
EC-192,
EC-205
Air fuel ratio (A/F) sensor 1 circuit EC-213
,
EC-223
,
EC-232
,
EC-241
,
EC-575

Throttle position sensor circuit 22EC-198
,
EC-320
,
EC-483
,
EC-485
,
EC-560
Accelerator pedal position sensor circuit 3 2 1EC-453
,
EC-547
,
EC-553
,
EC-567
Knock sensor circuit 23EC-335
Crankshaft position sensor (POS) circuit 2 2 EC-340
Camshaft position sensor (PHASE) circuit 3 2EC-347

TROUBLE DIAGNOSISEC-93
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
1 - 6: The numbers refer to the order of inspection.
(continued on next page)Vehicle speed signal circuit
2 3 33EC-442
Power steering pressure sensor circuit 23 3 EC-448
ECM 22333333333 EC-453,
EC-457
Park/Neutral position (PNP) switch circuit 3 3 3 33EC-465
Refrigerant pressure sensor circuit 233 4 EC-630
Electrical load signal circuit 3EC-596
Air conditioner circuit 223333333 3 2 AT C - 3 4
ABS actuator and electric unit (control unit)4EC-471
,
EC-472

or BRC-11
SYMPTOM
Refer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA

EC-94Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
SYSTEM — ENGINE MECHANICAL & OTHER
SYMPTOMReference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel tank 5
5 FL-10
Fuel piping
5 5 5 5 55FL-4
Vapor lock —
Valve deposit 5 555 55 5 —
Poor fuel (Heavy weight gaso-
line, Low octane) —
Air Air duct
55555 5 EM-15
Air cleaner
EM-15
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator) 5555 EM-15
Electric throttle control actuator
EM-17
Air leakage from intake manifold/
Collector/GasketEM-17
Cranking Battery
111111
11
SC-4
Generator circuit
SC-17
Starter circuit3 SC-10
Signal plate6 EM-37
Park/Neutral position (PNP)
switch4
AT- 1 0 5
Engine Cylinder head
55555 55 5EM-63
Cylinder head gasket 4 3
Cylinder block
66666 66 64
EM-78
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nism Timing chain
55555 55 5 EM-37
Camshaft
EM-46
Intake valve
3EM-63
Exhaust valve

TROUBLE DIAGNOSISEC-95
C
DE
F
G H
I
J
K L
M A
EC
Revision: November 2009 2006 QX56
1 - 6: The numbers refer to the order of inspection.Exhaust Exhaust manifold/Tube/Muffler/
Gasket 55555 55 5 EM-21
,
EX-
3Three way catalyst
Lubrica-
tion Oil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery/Oil cooler
55555 55 5EM-24
,
LU-
13 , LU-10 ,
LU-11
Oil level (Low)/Filthy oil LU-7
Cooling Radiator/Hose/Radiator filler cap
55555 55 45 CO-14
Thermostat
5CO-21
Water pump CO-19
Water galleryCO-8
Cooling fan5CO-17
Coolant level (Low)/Contami-
nated coolant 5
CO-10
IVIS (INFINITI Vehicle Immobilizer System —
NATS) 11
BL-137
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA

EC-96Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
Engine Control Component Parts LocationUBS00L06
BBIA0449E