2011 INFINITI QX56 steering

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

EC-372
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0550 PSP SENSOR
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 PSP SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between PSP sens or harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.
Is the 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.
Is inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
+
−Voltag e
(Approx.)
PSP sensor
Connector terminal F35 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
PSP sensor ECM
Connector Terminal Connector Terminal F35 3 F111 45 Existed
+ −Continuity
ECM
Connector Terminal F 111 1 0 Ground Existed
E80 174
175
Revision: 2010 May2011 QX56

P0550 PSP SENSOREC-373
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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NO >> Repair or replace error-detected parts.
6.CHECK PSP SENSOR SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between PSP sens or harness connector and ECM harness connector.
4. Also check harness for short to ground and to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair or replace error-detected parts.
7.CHECK PSP SENSOR
Refer to EC-373, "
Component Inspection (Power Steering Pressure Sensor)".
Is the inspection result normal?
YES >> GO TO 8.
NO >> Replace PSP sensor.
8.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Power Steering Pressure Sensor)INFOID:0000000006217872
1.CHECK POWER STEERING PRESSURE SENSOR
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
3. Start engine and let it idle.
4. Check the voltage between ECM harness connector terminals under the following conditions.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace power steering pressure sensor.
+ −
Continuity
PSP sensor ECM
Connector Terminal Connector Terminal F35 2 F111 39 Existed
ECM Condition Voltage (V)
Connector +–
Te r m i n a l Te r m i n a l
F111 39 45 Steering wheel Being turned 0.5 - 4.5
Not being turned 0.4 - 0.8
Revision: 2010 May2011 QX56

P1564 ASCD STEERING SWITCHEC-431
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P1564 ASCD STEERING SWITCH
DTC LogicINFOID:0000000006217935
DTC DETECTION LOGIC
NOTE:
If DTC P1564 is displayed with DTC P0605, first pe
rform the trouble diagnosis for DTC P0605. Refer to
EC-376, "
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.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 10 seconds.
2. Press MAIN switch for at least 10 seconds, then release it and wait at least 10 seconds.
3. Press CANCEL switch for at least 10 seconds, then release it and wait at least 10 seconds.
4. Press RESUME/ACCELERATE switch for at least 10 seconds, then release it and wait at least 10 sec-
onds.
5. Press SET/COAST switch for at least 10 seconds , then release it and wait at least 10 seconds.
6. Check DTC.
Is DTC detected?
YES >> Go to EC-431, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217936
1.CHECK ASCD STEERING SWITCH CIRCUIT
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “MAIN SW”, “CANCEL SW”, “RESUME/ACC SW” and “SET SW” in “DATA MONITOR” mode with
CONSULT-III.
3. Check each item indication under the following conditions.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1564 ASCD SW
(ASCD steering switch)  An excessively high voltage signal from the
ASCD steering switch is sent to ECM.
 ECM detects that input signal from the ASCD steering switch is out of the specified
range.
 ECM detects that the ASCD steering switch is stuck ON.  Harness or connectors
(The switch circuit is open or shorted.)
 ASCD steering switch
ECM
Monitor item Condition Indication
MAIN SW MAIN switch Pressed ON
Released OFF
CANCEL SW CANCEL switch Pressed ON
Released OFF
RESUME/ACC SW RESUME/ACCELERATE
switch Pressed ON
Released OFF
Revision: 2010 May2011 QX56

EC-432
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1564 ASCD STEERING SWITCH
WITHOUT CONSULT-III
1. Turn ignition switch ON.
2. Check the voltage between ECM harness connector terminals under the following conditions.
Is the inspection result normal?
YES >> GO TO 7.
NO >> GO TO 2.
2.CHECK ASCD STEERING SWITCH GRO UND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect combination switch harness connector.
4. Check the continuity between combination switch and ECM harness connector.
5. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
 Combination switch (spiral cable)
 Harness for open and short between ECM and combination switch
>> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK ASCD STEERING SWITCH INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT
1. Check the continuity between combination switch and ECM harness connector.
2. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
SET SW SET/COAST switch Pressed ON
Released OFF
ECM Condition Voltage (V)
Connector +–
Te r m i n a l Te r m i n a l
E80 128
(ASCD steering switch signal) 130MAIN switch: Pressed Approx. 0
CANCEL switch: Pressed Approx. 1
SET/COAST switch: Pressed Approx. 2
RESUME/ACCELERATE switch: Pressed Approx. 3
All ASCD steering switches: Released Approx. 4
Monitor item Condition Indication
Combination switch ECM
Continuity
Connector Terminal Connector Terminal
— 32 E80 130 Existed
Combination switch ECM Continuity
Connector Terminal Connector Terminal
— 25 E80 128 Existed
Revision: 2010 May2011 QX56