engine coolant INFINITI QX56 2011 Factory Repair Manual

EC-218
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0117, P0118 ECT SENSOR
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
3.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-218, "
Component Inspection (Engine Coolant Temperature Sensor)".
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace engine coolant temperature sensor.
4.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Engine Coolant Temperature Sensor)INFOID:0000000006217800
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature sensor harness connector.
3. Remove engine coolant temperature sensor.
4. Check resistance between engine coolant temperature sensor terminals by heating with hot water as shown in the figure.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace engine coolant temperature sensor. Refer to EM-86, "
Exploded View".
Terminals Condition Resistance (k Ω)
1 and 2 Temperature [ °C ( °F)] 20 (68) 2.35 - 2.73
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
JMBIA0080ZZ
Revision: 2010 May2011 QX56

EC-222
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0125 ECT SENSOR
P0125 ECT SENSOR
DTC LogicINFOID:0000000006288280
DTC DETECTION LOGIC
NOTE:
If DTC P0125 is displayed with P0117 or P0118,
first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-217, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
>> GO TO 2.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR FUNCTION
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check that “COOLAN TEMP/S” is above 10 °C (50 °F).
WITH GST
Follow the procedure “With CONSULT-III” above.
Is the temperature above 10
°C (50°F)?
YES >> INSPECTION END
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
1. Start engine and run it for 65 minutes at idle speed. If “COOLAN TEMP/S” increases to more than 10 °C (50 °F) within 65 minutes, stop engine because
the test result will be OK.
CAUTION:
Never overheat engine.
2. Check 1st trip DTC.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?
YES >> EC-222, "Diagnosis Procedure"
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288281
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-218, "
Component Inspection (Engine Coolant Temperature Sensor)".
Is the inspection result normal?
YES >> GO TO 2.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0125 ECT SENSOR
(Insufficient engine coolant
temperature for closed loop
fuel control)  Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.
 Engine coolant temperature is insufficient for closed loop fuel control.  Harness or connectors
(High resistance in the circuit)
 Engine coolant temperature sensor
 Thermostat
Revision: 2010 May2011 QX56

P0125 ECT SENSOREC-223
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
NO >> Replace engine coolant temperature sensor.
2.CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70 °C (158 °F)] condition, grasp lower radiator hose and confirm that the
engine coolant does not flow.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace thermostat. Refer to CO-20, "
Removal and Installation".
3.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Engine Coolant Temperature Sensor)INFOID:0000000006288610
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature sensor harness connector.
3. Remove engine coolant temperature sensor.
4. Check resistance between engine coolant temperature sensor
terminals by heating with hot water as shown in the figure.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace engine coolant temperature sensor. Refer to EM-86, "
Exploded View".
Terminals Condition Resistance (k Ω)
1 and 2 Temperature [ °C ( °F)] 20 (68) 2.35 - 2.73
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
JMBIA0080ZZ
Revision: 2010 May2011 QX56

EC-224
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0127 IAT SENSOR
P0127 IAT SENSOR
DTC LogicINFOID:0000000006288283
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road
test is expected to be easier, it is unnecessary to lift the vehicle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
1. Wait until engine coolant temperature is less than 90 °C (194 °F)
- Turn ignition switch ON.
- Select “DATA MONITOR” mode with CONSULT-III.
- Check the engine coolant temperature.
- If the engine coolant temperature is not less than 90 °C (194 °F), turn ignition switch OFF and cool down
engine.
NOTE:
Perform the following steps before engine coolant temperature is above 90 °C (194 °F).
2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Start engine.
5. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.
CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?
YES >> Proceed to EC-224, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288284
1.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-225, "
Component Inspection (Intake Air Temperature Sensor)".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace mass air flow sensor (with intake air temperature sensor).
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0127 IAT SENSOR-B1
(Intake air temperature too
high) Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor.  Harness or connectors
(The intake air temperature sensor
circuit is open or shorted)
 Intake air temperature sensor
Revision: 2010 May2011 QX56

EC-226
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0128 THERMOSTAT FUNCTION
P0128 THERMOSTAT FUNCTION
DTC LogicINFOID:0000000006288286
DTC DETECTION LOGIC
NOTE:
If DTC P0128 is displayed with DTC P0300, P0301,
P0302, P0303, P0304, P0305, P0306, P0307 or P0308,
first perform the trouble diagnosis for DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307,
P0308. Refer to EC-291, "
DTC Logic".
Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long
enough.
This is due to a leakage in the seal or the thermostat being stuck open.
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
 For best results, perform at ambient temperature of –10 °C (14 °F) or higher.
 For best results, perform at en gine coolant temperature of –10 °C (14 °F) to 52 °C (126 °F).
 Before performing the following procedure, do not add fuel.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
1. Turn A/C switch OFF.
2. Turn blower fan switch OFF.
3. Turn ignition switch ON.
4. Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.
5. Check the indication of “COOLAN TEMP/S”. If it is below 52 °C (126 °F), go to next step.
If it is above 52 °C (126 °F), cool engine down to less than 52 °C (126 °F). Then go to next step.
6. Start engine and drive vehicle for 10 consec utive minutes under the following conditions.
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “COOLAN TEMP/S” increases to more than 71 °C (160 °F) within 10 minutes, turn ignition switch
OFF because the test result will be OK.
7. Check 1st trip DTC.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?
YES >> Proceed to EC-227, "Diagnosis Procedure".
NO >> INSPECTION END
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0128 THERMSTAT FNCTN
(Thermostat function) The engine coolant temperature does not
reach to specified temperature even
though the engine has run long enough. Thermostat
 Leakage from sealing portion of thermostat
 Engine coolant temperature sensor
Vehicle speed More than 56 km/h (35 MPH)
Revision: 2010 May2011 QX56

P0128 THERMOSTAT FUNCTIONEC-227
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
Diagnosis ProcedureINFOID:0000000006288287
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-227, "
Component Inspection (Engine Coolant Temperature Sensor)".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace engine coolant temperature sensor.
2.CHECK THERMOSTAT
Remove and Check the thermostat. Refer to CO-20, "
Removal and Installation" and CO-21, "Inspection".
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace thermostat.
Component Inspection (Engine Coolant Temperature Sensor)INFOID:0000000006288288
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature sensor harness connector.
3. Remove engine coolant temperature sensor.
4. Check resistance between engine coolant temperature sensor
terminals by heating with hot water as shown in the figure.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace engine coolant temperature sensor.
Terminals Condition Resistance (k Ω)
1 and 2 Temperature [ °C ( °F)] 20 (68) 2.35 - 2.73
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
JMBIA0080ZZ
Revision: 2010 May2011 QX56

P0181 FTT SENSOREC-271
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0181 FTT SENSOR
DTC LogicINFOID:0000000006288289
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Turn ignition switch ON and wait at least 10 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-271, "Diagnosis Procedure".
NO >> GO TO 3.
3.CHECK ENGINE COOLANT TEMPERATURE
WITH CONSULT-III
1. Select “COOLAN TEMP/S” in “DATA MONITOR” with CONSULT-III.
2. Check “COOLAN TEMP/S” value.
WITH GST
Follow the procedure “With CONSULT-III” above.
“
COOLAN TEMP/S” less than 60°C (140°F)?
YES >> INSPECTION END
NO >> GO TO 4.
4.PERFORM DTC CONFIRMATION PROCEDURE-II
WITH CONSULT-III
1. Cool engine down until “COOLAN TEMP/S” is less than 60 °C (140 °F).
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?
YES >> Proceed to EC-271, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288290
1.CHECK DTC WITH COMBINATION METER
Refer to MWI-30, "
CONSULT-III Function".
Is the inspection result normal?
YES >> GO TO 2.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0181 FTT SENSOR
[Fuel tank temperature sensor
circuit range/performance] Rationally incorrect voltage from the sensor
is sent to ECM, compared with the voltage
signals from engine coolant temperature sen-
sor and intake air temperature sensor.  Harness or connectors
(The FTT sensor circuit is open or
shorted)
 Fuel tank temperature sensor
 Combination meter
Revision: 2010 May2011 QX56

P0191 FRP SENSOREC-279
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0191 FRP SENSOR
DTC LogicINFOID:0000000006288298
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start the engine and warm it up to the normal operating temperature. NOTE:
Warm up the engine until “COOLAN TEMP/S” on “DATA MONITOR” of CONSULT-III reaches at least
70 °C (158 °F).
2. Turn the ignition switch OFF and cool the engi ne until the engine coolant temperature reaches 35 °C
(95 °F) or less.
CAUTION:
 The difference between air temperature an d engine coolant temperature must be 5°C or less.
 Do not turn ignition switch ON.
3. Turn ignition switch ON and wait at least 60 seconds.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-279, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288299
1.CHECK FRP SENSOR POWER SUPPLY-I
1. Turn ignition switch OFF.
2. Disconnect FRP sensor connector.
3. Turn ignition switch ON.
4. Check the voltage between FRP s ensor harness connector terminals.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0191 Fuel rail pressure sensor Fuel rail pressure re
mains at more than
1.5 MPa (15 bar, 15.3 kg/cm
2, 217.5 psi)
for 0.2 seconds or more during ignition
ON.  Harness or connectors
(Fuel rail pressure sensor circuit is open or
shorted.)
(Power steering pressure sensor circuit is
open or shorted.)
(Low fuel pressure sensor circuit is open or
shorted.)
(The electrically-controlled cooling fan cou-
pling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Low fuel pressure sensor
 Electrically-controlled cooling fan coupling
Revision: 2010 May2011 QX56

P0196 EOT SENSOREC-283
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0196 EOT SENSOR
DTC LogicINFOID:0000000006288301
DTC DETECTION LOGIC
NOTE:
If DTC P0196 is displayed with P0197 or P0198, fi
rst perform the trouble diagnosis for DTC P0197,
P0198. Refer to EC-285, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and let it idle for 5 minutes and 10 seconds.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> EC-284, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
WITH CONSULT-III
1. Select “DATA MONITOR” mode with CONSULT-III.
2. Check that “COOLAN TEMP/S” indicates above 80 °C (176 °F).
If it is above 80 °C (176 °F), go to the following steps.
If it is below 80 °C (176 °F), warm engine up until “COOLAN TEMP/S” indicates more than 80 °C (176 °F).
Then perform the following steps.
3. Turn ignition switch OFF and soak the vehicle in a cool place.
4. Turn ignition switch ON.
NOTE:
Do not turn ignition switch OFF until step 8.
5. Select “DATA MONITOR” mode with CONSULT-III.
6. Check the following.
If they are within the specifi ed range, perform the following steps.
If they are out of the specified range, soak the vehicle to meet t he above conditions. Then perform the fol-
lowing steps.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0196 EOT SENSOR
(Engine oil temperature sen-
sor range/performance) Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signals
from engine coolant temperature sensor and in-
take air temperature sensor.  Harness or connectors
(The EOT sensor circuit is open or
shorted)
 Engine oil temperature sensor
COOLAN TEMP/S Below 40 °C (104 °F)
INT/A TEMP SE Below 40 °C (104 °F)
Difference between “COOLAN TEMP/S” and “INT/A TEMP SE” Within 6 °C (11 °F)
Revision: 2010 May2011 QX56

EC-292
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0300, P0301, P0302, P
0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Restart engine and let it idle for about 15 minutes.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-292, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
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. Start engine and drive the vehicle under similar conditions to (1st trip) Freeze Frame Data for a certain
time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
Similar conditions to (1st trip) Freeze Frame Data mean that the following conditions should be satisfied at
the same time.
CAUTION:
Always drive vehicle in safe manner according to tr affic conditions and obey all traffic laws when
driving.
Driving time varies according to the engine speed in the freeze frame data.
5. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-292, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217841
1.CHECK FOR INTAKE AIR LEAKAGE AND PCV HOSE
1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leakage.
3. Check PCV hose connection.
Is intake air leakage detected?
YES >> Discover air leakage location and repair.
NO >> GO TO 2.
2.CHECK FOR EXHAUST SYSTEM CLOGGING
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Base fuel schedule Base fuel schedule in the freeze frame data × (1 ± 0.1)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
Engine speed Time
Around 1,000 rpm Approximately 10 minutes
Around 2,000 rpm Approximately 5 minutes
More than 3,000 rpm Approximately 3.5 minutes
Revision: 2010 May2011 QX56