Infiniti M35/M45 Y50. Manual - part 677

DTC P0550 PSP SENSOR

EC-1181

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DTC P0550 PSP SENSOR

PFP:49763

Component Description

NBS005JH

Power steering pressure (PSP) sensor (1) is installed to the power
steering high-pressure tube and detects a power steering load.

●

Illustration shows the view from under the vehicle.

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

NBS005JI

Specification data are reference values.

On Board Diagnosis Logic

NBS005JJ

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-1193, "DTC P0643 SENSOR POWER SUPPLY"

 .

DTC Confirmation Procedure

NBS005JK

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-1183, "Diagnostic Proce-

dure"

 .

 WITH GST

Follow the procedure “WITH CONSULT-II” above.

PBIB2701E

MONITOR ITEM

CONDITION

SPECIFICATION

PW/ST SIGNAL

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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.

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Harness or connectors
(The sensor circuit is open or shorted)

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Power steering pressure sensor

SEF058Y

EC-1182

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DTC P0550 PSP SENSOR

Wiring Diagram

NBS005JL

TBWT1032E

DTC P0550 PSP SENSOR

EC-1183

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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

NBS005JM

1. 

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten ground screws on the body.
Refer to 

EC-864, "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/G

Power steering pressure 
sensor

[Engine is running]

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Steering wheel: Being turned

0.5 - 4.5V

[Engine is running]

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Steering wheel: Not being turned

0.4 - 0.8V

67

B/W

Sensor ground
(Power steering pressure 
sensor)

[Engine is running]

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Warm-up condition

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Idle speed

Approximately 0V

68

L/Y

Sensor power supply
(Power steering pressure 
sensor)

[Ignition switch: ON]

Approximately 5V

1.

Body ground M70

2.

Body ground M16

PBIB2782E

EC-1184

[VK45DE]

DTC P0550 PSP SENSOR

2. 

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect PSP sensor (1) harness connector.

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Illustration shows the view from under the vehicle.

2.

Turn ignition switch ON.

3.

Check voltage between PSP sensor terminal 1 and ground with
CONSULT-II or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3. 

DETECT MALFUNCTIONING PART 

Check the following.

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Harness connectors E206, E72

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Harness connectors E11, F2

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Harness for open or short between power steering pressure sensor and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

4. 

CHECK PSP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between PSP sensor terminal 3 and ECM terminal 67.
Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART 

Check the following.

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Harness connectors E206, E72

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Harness connectors E11, F2

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Harness for open or short between power steering pressure sensor and ECM

>> Repair open circuit or short to ground short to power in harness or connectors.

PBIB2701E

Voltage: Approximately 5V

PBIB0188E

Continuity should exist.