steering INFINITI QX56 2011 Factory Service Manual

EC-166
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternat
or, A/C compressor, etc. is excessive
- Noise from engine
- Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
- Valve clearance malfunction
- Intake valve timing control function malfunction
- Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 27.
16.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
 Crushed air ducts
 Malfunctioning seal of air cleaner element
 Uneven dirt of air cleaner element
 Improper specification of intake air system
Is the inspection result normal?
YES >> GO TO 18.
NO >> Repair or replace malfunctioning part, and then GO TO 17.
17.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2” AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2” and “B/FUE L SCHDL” in “SPEC” of “DATA MONITOR” mode, and
check that each indication is within the SP value.
Is the measurement value within the SP value?
YES >> INSPECTION END
NO >> “B/FUEL SCHDL” is more, “A/F ALPHA-B1” and “A /F ALPHA-B2” are less than the SP value: GO
TO 18.
18.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and then reconnect it again.
>> GO TO 19.
19.CHECK “A/F ALPHA-B1” AND “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1” and “A/F ALPHA-B2” in “ SPEC” of “DATA MONITOR” mode, and check that each
indication is within the SP value.
Is the measurement value within the SP value?
YES >> Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to EC-201, "Diagno-
sis Procedure". Then GO TO 26.
NO >> GO TO 20.
20.CHECK “MAS A/F SE-B1”
Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and check that the indication is within the SP
value.
Is the measurement value within the SP value?
YES >> GO TO 21.
NO >> More than the SP value: Replace malfuncti oning mass air flow sensor, and then GO TO 26.
21.REPLACE ECM
1. Replace ECM.
2. Perform EC-143, "
Work Procedure".
Revision: 2010 May2011 QX56

EC-276
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0190, P0192,
P0193 FRP SENSOR
P0190, P0192, P0193 FRP SENSOR
DTC LogicINFOID:0000000006288295
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 ON and wait at least 60 seconds.
2. Check DTC or 1st trip DTC.
Is DTC or 1st trip DTC detected?
YES >> Proceed to EC-276, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288296
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 sensor harness connector terminals.
Inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK FRP SENSOR POWER SUPPLY-II
Check the voltage between FRP sensor harness connector and the ground.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0190 Fuel rail pressure sensor
circuit low input and high in-
put Signal voltage from the fuel rail pressure
sensor remains at more than 4.84 V /
less than 0.2 V for 5 seconds or more.  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
P0192
Fuel rail pressure sensor
circuit low input Signal voltage from the fuel rail pressure
sensor remains at less than 0.37 V for 5
seconds or more.
P0193 Fuel rail pressure sensor
circuit high input Signal voltage from the fuel rail pressure
sensor remains at more than 3.46 V for 5
seconds or more.
FRP sensor
Voltag e
(Approx.)
Connector +
−
terminal
F26 1 3 5 V
Revision: 2010 May2011 QX56

P0190, P0192, P0193 FRP SENSOR
EC-277
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Is inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness connector for short to power and short to ground, between the following terminals.
Is inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "Diagnosis Procedure".
NO >> Repair or replace error-detected parts.
4.CHECK FRP SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between FRP sens or harness connector and ECM harness connector.
Is inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK ECM GROUND CIRCUIT
Check the continuity between ECM harness connector and the ground.
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Repair or replace error-detected parts.
+
−Vo l ta g e
(Approx.)
FRP sensor
Connector Terminal F26 1 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
FRP sensor ECM
Connector Terminal Connector Terminal F26 3 F111 40 Existed
ECM Ground Continuity
Connector Terminal
F 111 5
Ground Existed
E80 11 4
11 5
174
175
Revision: 2010 May2011 QX56

P0191 FRP SENSOREC-279
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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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

EC-280
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0191 FRP SENSOR
Inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK FRP SENSOR POWER SUPPLY-II
Check the voltage between FRP sensor harness connector and the ground.
Is inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness connector for short to power and short to ground, between the following terminals.
Is inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "Diagnosis Procedure".
NO >> Repair or replace error-detected parts.
4.CHECK FRP SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between FRP sens or harness connector and ECM harness connector.
Is inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK ECM GROUND CIRCUIT
Check the continuity between ECM harness connector and the ground.
FRP sensor Voltag e
(Approx.)
Connector +
−
terminal
F26 1 3 5 V
+ −Voltag e
(Approx.)
FRP sensor
Connector Terminal F26 1 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
FRP sensor ECM
Connector Terminal Connector Terminal F26 3 F111 40 Existed
Revision: 2010 May2011 QX56

EC-358
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0506 ISC SYSTEM
P0506 ISC SYSTEM
DescriptionINFOID:0000000006217861
The ECM controls the engine idle speed to a specified leve
l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng speed. The crankshaft position sensor detects the
actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is t he lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration and engine load (air conditioner, power steering and cooling fan
operation, etc.).
DTC LogicINFOID:0000000006217862
DTC DETECTION LOGIC
NOTE:
If DTC P0506 is displayed with ot her DTC, first perform the trouble diagnosis for the other DTC.
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.
If the target idle speed is ou t of the specified value, perform EC-148, "
Work Procedure", before con-
ducting DTC Confirmation Procedure.
TESTING CONDITION:
 Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
 Always perform the test at a temperature above −10 °C (14 °F).
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
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 run it for at least 1 minute at idle speed.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-358, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217863
1.CHECK INTAKE AIR LEAKAGE
1. Start engine and let it idle.
2. Listen for an intake air leakage after the mass air flow sensor.
Is intake air leakage detected?
YES >> Discover air leakage location and repair.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0506 ISC SYSTEM
(Idle speed control system
RPM lower than expected) The idle speed is less than the target idle
speed by 100 rpm or more.
 Electric throttle control actuator
 Intake air leakage
Revision: 2010 May2011 QX56

EC-360
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0507 ISC SYSTEM
P0507 ISC SYSTEM
DescriptionINFOID:0000000006217864
The ECM controls the engine idle speed to a specified leve
l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng speed. The crankshaft position sensor detects the
actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is t he lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration and engine load (air conditioner, power steering and cooling fan
operation, etc.).
DTC LogicINFOID:0000000006217865
DTC DETECTION LOGIC
NOTE:
If DTC P0507 is displayed with ot her DTC, first perform the trouble diagnosis for the other DTC.
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.
If the target idle speed is ou t of the specified value, perform EC-148, "
Work Procedure", before con-
ducting DTC Confirmation Procedure.
TESTING CONDITION:
 Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
 Always perform the test at a temperature above −10 °C (14 °F).
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
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 run it for at least 1 minute at idle speed.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-360, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217866
1.CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace malfunctioning part.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0507 ISC SYSTEM
(Idle speed control system
RPM higher than expected) The idle speed is more than the target idle
speed by 200 rpm or more.  Electric throttle control actuator
 Intake air leakage
 PCV system
Revision: 2010 May2011 QX56

P0527 COOLING FAN SPEED SENSOREC-367
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0527 COOLING FAN SPEED SENSOR
DTC LogicINFOID:0000000006217867
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 engine and warm it up to the normal operating temperature.
2. Keep the engine speed approximately 1,000 rpm at no load.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-367, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217868
1.CHECK COOLING FAN SPEED SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect electrically-controlled c ooling fan coupling harness connector.
3. Turn ignition switch ON.
4. Check the voltage between electrically-controlled cooling fan coupling harness connector terminals.
Is inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0527 Cooling fan speed sen-
sor circuit range/perfor-
mance The number of fan speed signals is 16 rpm or
less during engine rev.  Harness or connectors
(The Fuel rail pressure sensor circuit is
open or shorted.)
(The Power steering pressure sensor cir-
cuit is open or shorted)
(The Electrically-controlled cooling fan
coupling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Cooling fan speed sensor
 Electrically-controlled cooling fan cou- pling
 Cooling fan
 IPDM E/R
Electrically-controlled cooling fan coupling Vo l ta g e
(Approx.)
Connector +
−
terminal
F39 2 4 5 V
Revision: 2010 May2011 QX56

EC-368
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0527 COOLING FAN SPEED SENSOR
2.CHECK COOLING FAN SPEED SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between electrically-controlled cooling fan coupling harness connector and the ground.
Is inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness connector for short to power and short to ground, between the following terminals.
Is inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "Diagnosis Procedure".
NO >> Repair or replace error-detected parts.
4.CHECK COOLING FAN SPEED SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between electrically-contro lled cooling fan coupling harness connector and ECM har-
ness connector.
Is inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK ECM GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between ECM harness connector and the ground.
+
−Vol tag e
(Approx.)
Electrically-controlled cooling fan coupling
Connector terminalF39 2 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
Electrically-controlled cooling fan
coupling ECM
Connector Terminal Connector Terminal F 3 9 4 F 111 4 5 E x i s t e d
Revision: 2010 May2011 QX56

P0550 PSP SENSOREC-371
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0550 PSP SENSOR
DTC LogicINFOID:0000000006217870
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
1. Start engine and let it idle for at least 5 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-371, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217871
1.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect power steering pressure (PSP) sensor harness connector.
3. Turn ignition switch ON.
4. Check the voltage between PSP sensor harness connector terminals.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between PSP sensor harness connector and the ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0550 PW ST P SEN/CIRC
(Power steering pressure
sensor circuit) An excessively low or high voltage from the
sensor is sent to ECM.  Harness or connectors
(The Fuel rail pressure sensor circuit is
open or shorted.)
(The Power steering pressure sensor cir-
cuit is open or shorted)
(The Electrically-controlled cooling fan
coupling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Electrically-controlled cooling fan cou- pling
PSP sensor Vo l ta g e
(Approx.)
Connector +
−
terminal
F35 1 3 5 V
Revision: 2010 May2011 QX56