3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 LX570)

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Last Modified: 11-27-2007		1.6 C
Service Category: Engine/Hybrid System	Section: Engine Control
Model Year: 2008	Model: LX570	Doc ID: RM000001EY900FX
Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 LX570)

DTC

P0550

Power Steering Pressure Sensor Circuit Malfunction

DTC

P0552

Power Steering Pressure Sensor Circuit Low Input

DTC

P0553

Power Steering Pressure Sensor Circuit High Input

DESCRIPTION

The power steering oil pressure sensor is turned on when a power steering wheel load occurs by turning the steering wheel. The ECM regulates the engine idling RPM according to the voltage output of the sensor.

DTC Code	DTC Detection Condition	Trouble Area
P0550	An open or short in the power steering oil pressure sensor circuit is detected for more than 3 seconds after the engine switch is turned on (IG) (1 trip detection logic).	Open or short in power steering oil pressure sensor circuit Power steering oil pressure sensor ECM
P0552	An open in the power steering oil pressure sensor circuit is detected for more than 3 seconds after the engine switch is turned on (IG).	Open in power steering oil pressure sensor circuit Power steering oil pressure sensor ECM
P0553	A short in the power steering oil pressure sensor circuit is detected for more than 3 seconds after the engine switch is turned on (IG).	Short in power steering oil pressure sensor circuit Power steering oil pressure sensor ECM

WIRING DIAGRAM

MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to regulate the engine idling speed. When the sensor output voltage deviates from the normal operating range, the ECM determines that there is a malfunction in the power steering oil pressure sensor and stores DTC(s).

MONITOR STRATEGY

Related DTCs	P0550: Power steering pressure sensor range check (Chattering) P0552: Power steering pressure sensor range check (Low Resistance) P0553: Power steering pressure sensor range check (High Resistance)
Required sensors/Components (Main)	Power steering pressure sensor
Frequency of operation	Continuous
Duration	0.5 seconds
MIL operation	Immediate
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not stored	None
Time after starter signal ON to OFF	2 seconds or more

TYPICAL MALFUNCTION THRESHOLDS

P0550:

Power steering pressure sensor voltage

Below 0.28 V, or higher than 4.9 V

P0552:

Power steering pressure sensor voltage

Below 0.28 V

P0553:

Power steering pressure sensor voltage

Higher than 4.9 V

INSPECTION PROCEDURE

HINT:

If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
Read freeze frame data using the Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (ECM - POWER STEERING OIL PRESSURE SENSOR)

(a) Disconnect the C53 ECM connector.

(b) Disconnect the C28 power steering oil pressure sensor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C28-2 (PSP) - C53-72 (PSP)	Always	Below 1 Ω
C28-1 (VC) - C53-67 (VCV1)	Always	Below 1 Ω
C28-3 (E2) - C53-97 (ETHW)	Always	Below 1 Ω
C28-2 (PSP) or C53-72 (PSP) - Body ground	Always	10 kΩ or higher
C28-1 (VC) or C53-67 (VCV1) - Body ground	Always	10 kΩ or higher

2.	REPLACE POWER STEERING OIL PRESSURE SENSOR

(a) Replace the power steering oil pressure sensor .

3.	CONFIRM WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream on.

(d) Read the DTCs.

Result

Result	Proceed to
P0550, P0552 and/or P0553 are output	A
No DTC is output	B