Infiniti M45 (Y34). Manual - part 429

DTC P0550 PSP SENSOR

EC-405

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DTC P0550 PSP SENSOR

PFP:49763

Component Description

ABS002M2

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

ABS002M3

Specification data are reference values.

On Board Diagnosis Logic

ABS002M4

NOTE:
If DTC P0550 is displayed with DTC P1229, first perform the trouble diagnosis for DTC P1229.
Refer to 

EC-531

 .

The MIL will not light up for this diagnosis.

DTC Confirmation Procedure

ABS002M5

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-407, "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.
(Forward direction)

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

EC-406

DTC P0550 PSP SENSOR

Wiring Diagram

ABS002M6

TBWA0296E

DTC P0550 PSP SENSOR

EC-407

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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

ABS002M7

1. 

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten two ground screws. 
Refer to 

EC-141, "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)

89

B

Sensor ground

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 0V

103

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Sensor power supply

[Ignition switch: ON]

Approximately 5V

118

R

Power steering pressure 
sensor

[Engine is running]

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Steering wheel: Being turned.

0.5 - 4.0V

[Engine is running]

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Steering wheel: Not being turned.

0.4 - 0.8V

PBIB1118E

EC-408

DTC P0550 PSP SENSOR

2. 

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect power steering pressure (PSP) sensor harness con-
nector.

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 F6, E316

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Harness for open or short between ECM and PSP 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.

Disconnect ECM harness connector.

3.

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

4.

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.

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Harness connectors F6, E316

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Joint connector-30

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Harness for open or short between PSP sensor and ECM

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

PBIB0027E

Voltage: Approximately 5V

PBIB0188E

Continuity should exist.