EC-76Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
DTC Inspection Priority ChartUBS00GZX
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-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
Priority Detected items (DTC)
1
U1000 U1001 CAN communication line
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
P0705 Park/Neutral position (PNP) switch
P1229 Sensor power supply
P1610 - P1615 NATS
P1706 Park/Neutral position (PNP) switch
P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
TROUBLE DIAGNOSIS
EC-87
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Revision: August 20072004 QX56
1 - 6: The numbers refer to the order of inspection.Cooling Radiator/Hose/Radiator filler cap
55555 55 45CO-10
Thermostat 5CO-17
Water pum pCO-15
Water galleryCO-6
Cooling fan
5EC-410
Coolant level (Low)/Contami-
nated coolantCO-8
IVIS (Infinti Vehicle Immobilizer System —
NATS)11EC-63 or
BL-138
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-104Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
System readiness test (SRT) codes
Test values
Others
ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
DATA
MONI-
TORDATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STATUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS)××××
Camshaft position sensor (PHASE)××××
Mass air flow sensor×××
Engine coolant temperature sensor×××××
A/F sensor 1×××××
Heated oxygen sensor 2×××××
Vehicle speed sensor×× ××
Accelerator pedal position sensor×××
Throttle position sensor×××
Fuel tank temperature sensor××××
EVAP control system pressure
sensor×××
Intake air temperature sensor××× ×
Knock sensor×
Refrigerant pressure sensor××
Closed throttle position switch
(accelerator pedal position sensor
signal)××
Air conditioner switch××
Park/neutral position (PNP) switch×××
Stop lamp switch×××
Power steering pressure sensor×××
Battery voltage××
Load signal××
Fuel level sensor×××
ICC steering switch×××
ASCD steering switch×××
ICC brake switch×××
ASCD brake switch×××
EC-108Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
A/F ALPHA-B1 [%]×
The mean value of the air-fuel ratio feedback
correction factor per cycle is indicated.
When the engine is stopped, a certain
value is indicated.
This data also includes the data for the
air-fuel ratio learning control. A/F ALPHA-B2 [%]×
COOLAN TEMP/S
[°C] or [°F]××
The engine coolant temperature (determined
by the signal voltage of the engine coolant
temperature sensor) is displayed.
When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine
coolant temperature determined by the
ECM is displayed.
A/F SEN1 (B1) [V]××
The A/F signal computed from the input signal
of the A/F sensor 1 is displayed.
A/F SEN1 (B2) [V]×
HO2S2 (B1) [V]×
The signal voltage of the heated oxygen sen-
sor 2 is displayed.
HO2S2 (B2) [V]×
HO2S2 MNTR (B1)
[RICH/LEAN]×
Display of heated oxygen sensor 2 signal:
RICH: Means the amount of oxygen after
three way catalyst is relatively small.
LEAN: Means the amount of oxygen after
three way catalyst is relatively large.
When the engine is stopped, a certain
value is indicated.
HO2S2 MNTR (B2)
[RICH/LEAN]×
VHCL SPEED SE
[km/h] or [mph]××
The vehicle speed computed from the vehicle
speed signal sent from combination meter is
displayed.
BATTERY VOLT
[V]××
The power supply voltage of ECM is dis-
played.
ACCEL SEN 1 [V]××
The accelerator pedal position sensor signal
voltage is displayed.
ACCEL SEN 2 [V]×Accelerator pedal position sensor 2
signal is converted by ECM internally.
Thus, it differs from ECM terminal volt-
age signal.
THRTL SEN 1 [V]××
The throttle position sensor signal voltage is
displayed.
THRTL SEN 2 [V]×Throttle position sensor 2 signal is
converted by ECM internally. Thus, it
differs from ECM terminal voltage sig-
nal.
FUEL T/TEMP SE
[°C] or [°F]×
The fuel temperature (determined by the sig-
nal voltage of the fuel tank temperature sen-
sor) is displayed.
INT/A TEMP SE
[°C] or [°F]××
The intake air temperature (determined by the
signal voltage of the intake air temperature
sensor) is indicated.
EVAP SYS PRES
[V]×
The signal voltage of EVAP control system
pressure sensor is displayed.
FUEL LEVEL SE
[V]×
The signal voltage of the fuel level sensor is
displayed.
START SIGNAL
[ON/OFF]××
Indicates start signal status [ON/OFF] com-
puted by the ECM according to the signals of
engine speed and battery voltage.After starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF]××
Indicates idle position [ON/OFF] computed by
ECM according to the accelerator pedal posi-
tion sensor signal.
AIR COND SIG
[ON/OFF]××
Indicates [ON/OFF] condition of the air condi-
tioner switch as determined by the air condi-
tioner signal. Monitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
DTC P1217 ENGINE OVER TEMPERATURE
EC-411
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Revision: August 20072004 QX56
On Board Diagnosis LogicUBS00H8V
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
This self-diagnosis has the one trip detection logic.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant. Refer to CO-8, "
Changing Engine
Coolant" . Also, replace the engine oil. Refer to LU-8, "Changing Engine Oil" .
1. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to
use coolant with the proper mixture ratio. Refer to MA-11, "
ANTI-FREEZE COOLANT MIXTURE
RATIO" .
2. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
Overall Function CheckUBS00H8W
Use this procedure to check the overall function of the cooling fan. During this check, a DTC might not be con-
firmed.
WA RN ING:
Never remove the radiator cap when the engine is hot. Serious burns could be caused by high pres-
sure fluid escaping from the radiator.
Wrap a thick cloth around cap. Carefully remove the cap by turning it a quarter turn to allow built-up
pressure to escape. Then turn the cap all the way off.
WITH CONSULT-II
1. Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-415,
"Diagnostic Procedure" .
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-415,
"Diagnostic Procedure" .
3. Turn ignition switch ON.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217Engine over tempera-
ture (Overheat)
Cooling fan does not operate properly (Over-
heat).
Cooling fan system does not operate prop-
erly (Overheat).
Engine coolant was not added to the system
using the proper filling method.
Engine coolant is not within the specified
range.
Harness or connectors
(The cooling fan circuit is open or
shorted.)
Cooling fan
Radiator hose
Radiator
Radiator cap
Water pump
Thermostat
For more information, refer to EC-418,
"Main 12 Causes of Overheating" .
SEF 6 21 W
EC-412Revision: August 2007
DTC P1217 ENGINE OVER TEMPERATURE
2004 QX56
4. Perform “COOLING FAN” in “ACTIVE TEST” mode with CON-
SULT-II.
5. If the results are NG, go to EC-415, "
Diagnostic Procedure" .
WITH GST
1. Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-415,
"Diagnostic Procedure" .
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-415,
"Diagnostic Procedure" .
3. Disconnect engine coolant temperature sensor harness connec-
tor.
4. Connect 150Ω resistor to engine coolant temperature sensor
harness connector.
5. Start engine and make sure that cooling fan operates at higher
speed than low speed.
Be careful not to overheat engine.
6. If NG, go to EC-415, "
Diagnostic Procedure" .
SEF 6 46 X
SEF 6 21 W
SEF 8 82 V
EC-418Revision: August 2007
DTC P1217 ENGINE OVER TEMPERATURE
2004 QX56
5. CHECK INTERMITTENT INCIDENT
Perform EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> Replace IPDM E/R. Refer to PG-17, "IPDM E/R (INTELLIGENT POWER DISTRIBUTION MOD-
ULE ENGINE ROOM)" .
NG >> Repair or replace harness connectors.
Main 12 Causes of OverheatingUBS00H8Z
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to CO-4, "
OVERHEATING CAUSE ANALYSIS" . Engine Step Inspection item Equipment Standard Reference page
OFF 1
Blocked radiator
Blocked condenser
Blocked radiator grille
Blocked bumper
Visual No blocking —
2
Coolant mixtureCoolant tester 50 - 50% coolant mixtureMA-10, "RECOM-
MENDED FLUIDS AND
LUBRICANTS"
3Coolant levelVisual Coolant up to MAX level
in reservoir tank and radi-
ator filler neckCO-8, "Changing Engine
Coolant"
4Radiator capPressure tester 59 - 98 kPa
(0.6 - 1.0 kg/cm2 , 9 - 14
psi) (Limit)CO-8, "
CHECKING RES-
ERVOIR CAP"
ON*25Coolant leaksVisual No leaksCO-8, "CHECKING
COOLING SYSTEM FOR
LEAKS"
ON*26ThermostatTouch the upper and
lower radiator hosesBoth hoses should be hotCO-17, "THERMOSTAT
AND WATER PIPING"
ON*17Cooling fanCONSULT-II Operating See trouble diagnosis for
DTC P1217 (EC-410,
"DTC P1217 ENGINE
OVER TEMPERA-
TURE" ).
OFF 8
Combustion gas leakColor checker chemical
tester 4 Gas analyzerNegative —
ON*
39Coolant temperature
gaugeVisual Gauge less than 3/4
when driving—
Coolant overflow to
reservoir tankVisual No overflow during driving
and idlingCO-8, "Changing Engine
Coolant"
OFF*410Coolant return from
reservoir tank to radia-
torVisual Should be initial level in
reservoir tankCO-8, "Changing Engine
Coolant"
OFF 11Cylinder headStraight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)EM-64, "Inspection After
Disassembly"
12Cylinder block and pis-
tonsVisual No scuffing on cylinder
walls or pistonEM-89, "Inspection After
Disassembly"
ENGINE ASSEMBLY
EM-71
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Revision: August 20072004 QX56
5. Remove the cowl extension. Refer to EI-18, "Removal and Installation" .
6. Remove engine room cover using power tools.
7. Remove the air duct and air cleaner case assembly. Refer to EM-14, "
REMOVAL" .
8. Disconnect vacuum hose between vehicle and engine and set it aside.
9. Remove the radiator assembly and hoses. Refer to CO-10, "
REMOVAL" .
10. Remove the drive belts. Refer to EM-12, "
Removal" .
11. Remove the fan blade. Refer to CO-13, "
REMOVAL" .
12. Disconnect the engine room harness from the fuse box and set it aside for easier work.
13. Disconnect the ECM.
14. Disconnect the engine room harness from the engine side and set it aside for easier work.
15. Disconnect the engine harness grounds.
16. Disconnect the reservoir tank for power steering from engine and move it aside for easier work.
17. Disconnect power steering oil pump from engine. Move it from its location and secure with a rope for eas-
ier work. Refer to PS-26, "
REMOVAL" .
18. Remove the A/C compressor bolts and set aside. Refer to ATC-166, "
REMOVAL" .
19. Disconnect brake booster vacuum line.
20. Disconnect EVAP line.
21. Disconnect the fuel hose at the engine side connection. Refer to EM-29, "
REMOVAL" .
22. Disconnect the heater hoses at cowl, and install plugs to avoid leakage of engine coolant.
23. Remove the A/T oil level indicator and indicator tube upper bolts.
24. Remove the A/T. Refer to AT-255, "
Removal and Installation (4x2)" , or AT-258, "Removal and Installation
(4x4)" .
25. Install engine slingers into left bank cylinder head and right bank
cylinder head.
26. Lift with hoist and secure the engine in position.
27. Remove engine assembly from vehicle, avoiding interference
with vehicle body.
CAUTION:
Before and during this lifting, always check if any har-
nesses are left connected.
28. Remove alternator. Refer to SC-27, "
REMOVAL" .
29. Remove engine mounting insulator and bracket using power tool.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
When replacing an engine or transmission you must make sure the dowels are installed correctly
during re-assembly.
Improper alignment caused by missing dowels may cause vibration, oil leaks or breakage of driv-
etrain components.
WBIA0464E
Engine slinger torque: 45.0 N·m (4.6 kg-m, 33 ft-lb)
PBIC1556E