Infiniti Q45. Manual - part 460

DTC P0507 ISC SYSTEM

EC-479

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Diagnostic Procedure

NBS001YU

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.

3. 

REPLACE ECM

1.

Stop engine.

2.

Replace ECM.

3.

Perform initialization of IVIS (NATS) system and registration of all IVIS (NATS) ignition key IDs. Refer to

BL-202, "ECM Re-Communicating Function"

 .

4.

Perform 

EC-77, "VIN Registration"

 .

5.

Perform 

EC-77, "Accelerator Pedal Released Position Learning"

 .

6.

Perform 

EC-78, "Throttle Valve Closed Position Learning"

 .

7.

Perform 

EC-78, "Idle Air Volume Learning"

 .

>> INSPECTION END

EC-480

DTC P0550 PSP SENSOR

DTC P0550 PSP SENSOR

PFP:49763

Component Description

NBS001YV

Power steering pressure (PSP) sensor 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.

CONSULT-II Reference Value in Data Monitor Mode

NBS001YW

Specification data are reference values.

On Board Diagnosis Logic

NBS001YX

The MIL will not light up for this diagnosis.

NOTE:
If DTC P0550 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643.
Refer to 

EC-492, "DTC P0643 SENSOR POWER SUPPLY"

 .

DTC Confirmation Procedure

NBS001YY

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

 WITH CONSULT-II

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

Start engine and let it idle for at least 5 seconds.

4.

If 1st trip DTC is detected, go to 

EC-482, "Diagnostic Procedure"

.

 WITH GST

Follow the procedure WITH CONSULT-II above.

PBIB0027E

MONITOR ITEM

CONDITION

SPECIFICATION

PW/ST SIGNAL

●

Engine: After warming up, idle the 
engine

Steering wheel: Not being turned

OFF

Steering wheel: Being turned

ON

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

SEF058Y

DTC P0550 PSP SENSOR

EC-481

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Wiring Diagram

NBS001YZ

TBWM0556E

EC-482

DTC P0550 PSP SENSOR

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnostic Procedure

NBS001Z0

1. 

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten three ground screws on the body.
Refer to 

EC-154, "Ground Inspection"

 .

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

12

R

Power steering pressure 
sensor

[Engine is running]

●

Steering wheel: Being turned

0.5 - 4.5V

[Engine is running]

●

Steering wheel: Not being turned

0.4 - 0.8V

67

B

Sensor ground
(MAF sensor, IAT sensor, 
ECT sensor, FTT sensor, 
EVAP control system pres-
sure sensor, PSP sensor, 
ICC steering switch, ASCD 
steering switch, Refrigerant 
pressure sensor)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 0V

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Sensor power supply
(Power steering pressure 
sensor)

[Ignition switch: ON]

Approximately 5V

PBIB2417E