2011 INFINITI QX56 steering

EC-148
< BASIC INSPECTION >[VK56VD]
IDLE AIR VOLUME LEARNING
IDLE AIR VOLUME LEARNING
DescriptionINFOID:0000000006217750
Idle Air Volume Learning is a function of ECM to learn
the idle air volume that keeps engine idle speed within
the specific range. It must be perfo rmed under the following conditions:
 Each time the electric throttle control actuator or ECM is replaced.
 Idle speed or ignition timing is out of the specification.
Work ProcedureINFOID:0000000006217751
1.PRECONDITIONING
Check that all of the following conditions are satisfied.
Learning will be cancelled if any of the follo wing conditions are missed for even a moment.
 Battery voltage: More than 12.9 V (At idle)
 Engine coolant temperature: 70 - 105 °C (158 - 221 °F)
 Selector lever position: P or N
 Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine is
started the headlamp will not illuminate.
 Steering wheel: Neutral (Straight-ahead position)
 Vehicle speed: Stopped
 Transmission: Warmed-up
- With CONSULT-III: Drive vehicle until “ATF TEMP 2” in “DATA MONITOR” mode of “A/T” system indicates
less than 0.9 V.
- Without CONSULT-III: Drive vehicle for 10 minutes.
Will CONSULT-III be used?
YES >> GO TO 2.
NO >> GO TO 3.
2.PERFORM IDLE AIR VOLUME LEARNING
WITH CONSULT-III
1. Perform Accelerator Pedal Released Position Learning. Refer to EC-146, "
Work Procedure".
2. Perform Throttle Valve Closed Position Learning. EC-147, "
Work Procedure".
3. Start engine and warm it up to normal operating temperature.
4. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.
5. Touch “START” and wait 20 seconds.
Is
“CMPLT” displayed on CONSULT-III screen?
YES >> GO TO 4.
NO >> GO TO 5.
3.PERFORM IDLE AIR VOLUME LEARNING
WITHOUT CONSULT-III
NOTE:
 It is better to count the ti me accurately with a clock.
 It is impossible to switch the di agnostic mode when an accelerator pedal position sensor circuit has
a malfunction.
1. Perform Accelerator Pedal Released Position Learning. Refer to EC-146, "
Work Procedure".
2. Perform Throttle Valve Closed Position Learning. EC-147, "
Work Procedure".
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Confirm that accelerator pedal is fully releas ed, turn ignition switch ON and wait 3 seconds.
6. Repeat the following procedure quickly 5 times within 5 seconds.
- Fully depress the accelerator pedal.
- Fully release the accelerator pedal.
7. Wait 7 seconds, fully depress the accelerator pedal for approx. 20 seconds until the MIL stops blinking
and turns ON.
8. Fully release the accelerator pedal within 3 seconds after the MIL turns ON.
Revision: 2010 May2011 QX56

TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-161
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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DTC/CIRCUIT DIAGNOSIS
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DescriptionINFOID:0000000006217760
The specification (SP) value indicates the tolerance of
the value that is displayed in “SPEC” in “DATA MONI-
TOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC”
in “DATA MONITOR” mode is within the SP value, t he Engine Control System is confirmed OK. When the
value in “SPEC” in “DATA MONITOR” mode is NOT wit hin the SP value, the Engine Control System may have
one or more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not illuminate
the MIL.
The SP value will be displayed for the following items:
 B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correc- tion)
 A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
 MAS A/F SE-B1/B2 (The signal voltage of the mass air flow sensor)
 IDLE FUEL PRES MAX/MIN (the signal voltage of the fuel rail pressure sensor)
Component Function CheckINFOID:0000000006217761
1.PRECONDITIONING
Check that all of the following conditions are satisfied.
TESTING CONDITION
 Vehicle driven distance: More than 5,000 km (3,107 miles)
 Barometric pressure: 98.3 - 104.3 kPa (0.983 - 1.043 bar, 1.003 - 1.064 kg/cm
2, 14.25 - 15.12 psi)
 Atmospheric temperature: 20 - 30 °C (68 - 86 °F)
 Engine coolant temperature: 75 - 95 °C (167 - 203 °F)
 Transmission: Warmed-up
- After the engine is warmed up to normal operating temperat ure, drive vehicle until “ATF TEMP 2” (A/T fluid
temperature sensor signal) indicates more than 60 °C (140 °F).
 Electrical load: Not applied
- Rear window defogger switch, air conditioner switch and li ghting switch are OFF. Steering wheel is straight
ahead.
 Engine speed: Idle
 Gear position: Neutral ( or parking)
>> GO TO 2.
2.PERFORM SPEC IN DATA MONITOR MODE
WITH CONSULT-III
NOTE:
Perform “SPEC” in “DATA MONITOR” mode in maximum scale display.
1. Perform EC-139, "
Work Procedure".
2. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2”, “MAS A/F SE-B1” in “SPEC” of “DATA
MONITOR” mode with CONSULT-III.
3. Check that monitor items are within the SP value.
Is the measurement value within the SP value?
YES >> INSPECTION END
NO >> Proceed to EC-162, "
Diagnosis Procedure".
Revision: 2010 May2011 QX56

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