2009 INFINITI QX56 check engine

EC-272
< COMPONENT DIAGNOSIS >[VK56DE]
P0500 VSS
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to
EC-272, "Diagnosis Procedure"
.
Overall Function CheckINFOID:0000000003771544
Use this procedure to check the overall function of the v ehicle speed signal circuit. During this check, a 1st trip
DTC might not be confirmed.
WITH GST
1. Lift up drive wheels.
2. Start engine.
3. Read vehicle speed signal in Service $01 with GST. The vehicle speed signal on GST should be able to exceed 10 km/h (6 MPH) when rotating wheels with
suitable gear position.
4. If NG, go to EC-272, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771545
1.CHECK DTC WITH ABS ACTUATOR AN D ELECTRIC UNIT (CONTROL UNIT)
Refer to BRC-24, "CONSULT-III Function (ABS)"
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK COMBINATION METER FUNCTION
Refer to MWI-5
.
>> INSPECTION END
B/FUEL SCHDL 6.9 - 31.8 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
Revision: December 20092009 QX56

P0506 ISC SYSTEMEC-273
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P0506 ISC SYSTEM
DescriptionINFOID:0000000003771546
NOTE:
If DTC P0506 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
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 (POS) 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.).
On Board Diagnosis LogicINFOID:0000000003771547
DTC Confirmation ProcedureINFOID:0000000003771548
NOTE:
 If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
 If the target idle speed is ou t of the specified value, perform EC-18, "Idle Air Volume Learning"
,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-495, "Idle
Speed and Ignition Timing".
TESTING CONDITION:
 Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
 Always perform the test at a temperature above −10 °C (14 °F).
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-273, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771549
1.CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 2.
NG >> Discover air leak location and repair.
2.REPLACE ECM
1. Stop engine.
2. Replace ECM.
3. Perform initialization of IVIS(NATS) system and regist ration of all IVIS(NATS) ignition key IDs. Refer to
SEC-6, "ECM RE-COMMUNICATING FUNCT ION : Special Repair Requirement"
.
4. Perform EC-17, "VIN Registration"
.
5. Perform EC-18, "Accelerator Pedal Released Position Learning"
.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0506
0506 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 leak
Revision: December 20092009 QX56

P0507 ISC SYSTEMEC-275
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P0507 ISC SYSTEM
DescriptionINFOID:0000000003771550
NOTE:
If DTC P0507 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
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 (POS) 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.).
On Board Diagnosis LogicINFOID:0000000003771551
DTC Confirmation ProcedureINFOID:0000000003771552
NOTE:
 If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
 If the target idle speed is ou t of the specified value, perform EC-18, "Idle Air Volume Learning"
,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the EC-495, "Idle
Speed and Ignition Timing".
TESTING CONDITION:
 Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
 Always perform the test at a temperature above −10 °C (14 °F).
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-275, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771553
1.CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Discover air leak location and repair.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0507
0507 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 leak
 PCV system
Revision: December 20092009 QX56

P0550 PSP SENSOREC-277
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P0550 PSP SENSOR
Component DescriptionINFOID:0000000003771554
Power steering pressure (PSP) sensor (1) is installed to the power
steering high-pressure tube and detects a power steering load. This
sensor is a potentiometer which transforms the power steering load
into output voltage, and emits the voltage signal to the ECM. The
ECM controls the electric throttle
control actuator and adjusts the
throttle valve opening angle to increase the engine speed and
adjusts the idle speed for the increased load.
On Board Diagnosis LogicINFOID:0000000003771555
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-285
.
DTC Confirmation ProcedureINFOID:0000000003771556
1. If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and let it idle for at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-277, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771557
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
BBIA0741E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0550
0550 Power steering pressure
sensor circuit An excessively low or high voltage from the
sensor is sent to ECM.  Harness or connectors
(The sensor circuit is open or shorted)
 Power steering pressure sensor
BBIA0354E
Revision: December 20092009 QX56

P0550 PSP SENSOREC-279
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Component InspectionINFOID:0000000003771558
POWER STEERING PRESSURE SENSOR
1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.
3. Check voltage between ECM terminal 12 and ground under the
following conditions.
Condition Voltage
Steering wheel: Being turned. 0.5 - 4.5V
Steering wheel: Not being turned. 0.4 - 0.8V
MBIB0126E
Revision: December 20092009 QX56

EC-282
< COMPONENT DIAGNOSIS >[VK56DE]
P0605 ECM
P0605 ECM
Component DescriptionINFOID:0000000003771563
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The ECM controls the engine.
On Board Diagn
osis LogicINFOID:0000000003771564
This self-diagnosis has one or two trip detection logic.
FAIL-SAFE MODE
ECM enters fail-safe mode when the malfunction A is detected.
DTC Confirmation ProcedureINFOID:0000000003771565
Perform PROCEDURE FOR MALFUNCTION A first. If th e 1st trip DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION B. If there is no malfunction on PROCEDURE FOR MALFUNCTION
B, perform PROCEDURE FOR MALFUNCTION C.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
PROCEDURE FOR MALFUNCTION A
1. Turn ignition switch ON.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-283, "Diagnosis Procedure"
PROCEDURE FOR MALFUNCTION B
1. Turn ignition switch ON and wait at least 1 second.
2. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-283, "Diagnosis Procedure"
.
PROCEDURE FOR MALFUNCTION C
1. Turn ignition switch ON and wait at least 1 second.
2. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
PBIB1164E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0605
0605 Engine control module A) ECM calculation function is malfunctioning.
ECM
B) ECM EEP-ROM system is malfunctioning.
C) ECM self shut-off function is malfunctioning.
Detected items Engine operation condition in fail-safe mode
Malfunction A  ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx.
5 degrees) by the return spring.
 ECM deactivates ASCD operation.
Revision: December 20092009 QX56

P0643 SENSOR POWER SUPPLYEC-285
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P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000003771567
This self-diagnosis has the on
e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771568
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-285, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771569
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643 Sensor power supply circuit
short ECM detects a voltage of power source
for sensor is excessively low or high.  Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Battery current sensor circuit is shorted.)
(Refrigerant pressure se nsor circuit is short-
ed.)
(EVAP control system pressure sensor circuit
is shorted.)
 Accelerator pedal position sensor
 Power steering pressure sensor
 Refrigerant pressure sensor
 EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
BBIA0354E
Revision: December 20092009 QX56

EC-286
< COMPONENT DIAGNOSIS >[VK56DE]
P0643 SENSOR POWER SUPPLY
NG >> Repair or replace ground connections.
2.CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3.CHECK SENSOR POWER SUPPLY CIRCUITS
Check harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4.CHECK COMPONENTS
Check the following.
 EVAP control system pressure sensor (Refer to EC-244, "Component Inspection"
.)
 Power steering pressure sensor (Refer to EC-279, "Component Inspection"
.)
 Battery current sensor (Refer to EC-310, "Component Inspection"
.)
 Refrigerant pressure sensor
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5.CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-376, "Component Inspection"
.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
JMBIA0601ZZ
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3
EC-432, "Wiring Diagram - ENGINE
CONTROL SYSTEM -"
49Refrigerant pressure sensor terminal 1
Battery current sensor terminal 1
68 Power steering pressure sensor terminal 1
90 APP sensor terminal 7
Revision: December 20092009 QX56