Infiniti F50. Manual - part 440

DTC P0550 PSP SENSOR

EC-401

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DTC P0550 PSP SENSOR

PFP:49763

Component Description

EBS00MGB

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

EBS00MGC

Specification data are reference values.

On Board Diagnosis Logic

EBS00MGD

The MIL will not light up for this diagnosis.

DTC Confirmation Procedure

EBS00MGE

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-403, "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 is in neutral position.
(Forward direction)

OFF

Steering wheel is 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

EC-402

DTC P0550 PSP SENSOR

Wiring Diagram

EBS00MGF

TBWM0160E

DTC P0550 PSP SENSOR

EC-403

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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

EBS00MGG

1. 

RETIGHTEN GROUND SCREWS

1.

Turn ignition switch “OFF”.

2.

Loosen and retighten engine ground screws.

>> GO TO 2.

2. 

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect PSP sensor harness connector.

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.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

89

B

Sensor ground

[Engine is running]

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Warm-up condition

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Idle speed

Approximately 0V

103

L

Sensor power supply

[Ignition switch “ON”]

Approximately 5V

118

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Power steering pressure 
sensor

[Engine is running]

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Steering wheel is being turned.

0.5 - 4.0V

[Engine is running]

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Steering wheel is not being turned.

0.4 - 0.8V

PBIB0011E

PBIB0027E

Voltage: Approximately 5V

PBIB0188E

EC-404

DTC P0550 PSP SENSOR

3. 

DETECT MALFUNCTIONING PART

Check the following.

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Harness connectors F5, E315

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

>> 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.

Check harness continuity between PSP sensor terminal 3 and ECM terminal 89.
Refer to Wiring Diagram.

3.

Also check harness for short to power.

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART 

Check the following.

●

Harness connectors F5, E315

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Joint connector-30

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

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

6. 

CHECK PSP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminal 118 and PSP sensor terminal 2.
Refer to Wiring Diagram.

3.

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

OK or NG

OK

>> GO TO 8.

NG

>> GO TO 7.

7. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors F5, E315

●

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

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

8. 

CHECK PSP SENSOR

Refer to 

EC-406, "Component Inspection"

 .

OK or NG

OK

>> GO TO 9.

NG

>> Replace PSP sensor.

Continuity should exist.

Continuity should exist.