Power Steering: Overview Lexus RX II рестайлинг

DESCRIPTION

The torque sensor converts rotation torque input to the steering wheel into an electrical signal and sends it to the ECU. Based on this signal, the ECU detects steering effort.

DTC TROUBLE DETECTION ITEM CHART

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1. CHECK HARNESS AND CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND TORQUE SENSOR) Disconnect the P42 connector from the power steering ECU assembly. Disconnect the P44 connector from the torque sensor. Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P44-1 (INCS) - P42-8 (INCS) Always Below 1 ohms P44-2 (INSN) - P42-7 (INSN) Always Below 1 ohms P44-4 (TRQV) - P42-1 (TRQV) Always Below 1 ohms P44-5 (OUCS) - P42-10 (OUCS) Always Below 1 ohms P44-6 (OUSN) - P42-9 (OUSN) Always Below 1 ohms P44-7 (TQG2) - P42-14 (TQG2) Always Below 1 ohms P44-8 (TRQG1) - P42-12 (TQG1) Always Below 1 ohms P44-1 (INCS) - Body ground Always 10 kohms or higher P44-2 (INSN) - Body ground Always 10 kohms or higher P44-4 (TRQV) - Body ground Always 10 kohms or higher P44-5 (OUCS) - Body ground Always 10 kohms or higher P44-6 (OUSN) - Body ground Always 10 kohms or higher P44-7 (TQG2) - Body ground Always 10 kohms or higher P44-8 (TRQG1) - Body ground Always 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT POWER STEERING LINK ASSEMBLY (TORQUE SENSOR) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P44-1 (INCS) - P44-7 (TQG2) Always 90 to 170 ohms P44-2 (INSN) - P44-7 (TQG2) Always 300 to 430 ohms P44-4 (TRQV) - P44-8 (TRQG1) Always 4 to 14 ohms P44-5 (OUCS) - P44-7 (TQG2) Always 90 to 170 ohms P44-6 (OUSN) - P44-7 (TQG2) Always 300 to 430 ohms NOTE: If replacing the power steering link assembly, clear the rotation angle sensor calibration value, initialize the rotation angle sensor value, and calibrate torque sensor zero point (See «CALIBRATION» ). NG: REPLACE POWER STEERING LINK ASSEMBLY OK: Go to next step
3. REPLACE POWER STEERING ECU ASSEMBLY Replace the power steering ECU assembly (See «POWER STEERING ECU» ). NEXT: Go to next step
4. INITIALIZE ROTATION ANGLE SENSOR VALUE AND CALIBRATE TORQUE SENSOR ZERO POINT Initialize the rotation angle sensor value and calibrate the torque sensor zero point (See «CALIBRATION» ). NEXT: Go to next step
5. RECONFIRM DTC Check for DTCs (See «DTC CHECK / CLEAR» ). Is DTC C1511, C1512 or C1513 output? OK: DTC is not output. NOTE: If replacing the power steering link assembly, clear the rotation angle sensor calibration value, initialize the rotation angle sensor value, and calibrate torque sensor zero point (See «CALIBRATION» ). NG: REPLACE POWER STEERING LINK ASSEMBLY OK: END

These DTCs do not indicate a malfunction. The power steering ECU assembly outputs these DTCs when it determines that rotation angle sensor value initialization and torque sensor zero point calibration have not been performed.

DTC TROUBLE DETECTION ITEM CHART

These DTCs do not indicate a malfunction. The power steering ECU assembly outputs these DTCs when it determines that rotation angle sensor value initialization and torque sensor zero point calibration are incomplete.

DTC DETECTION CONDITION CHART

The power steering ECU assembly supplies current to the power steering motor through this circuit.

DTC DETECTION ITEM CHART

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1. CHECK HARNESS AND CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND POWER STEERING MOTOR) Disconnect the P42 connector from the power steering ECU assembly. Disconnect the P43 connector from the power steering motor. Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P42-5 (U) - P43-3 (U) Always Below 1 ohms P42-11 (V) - P43-1 (V) Always Below 1 ohms P42-6 (W) - P43-2 (W) Always Below 1 ohms P42-5 (U) - Body ground Always 10 kohms or higher P42-11 (V) - Body ground Always 10 kohms or higher P42-6 (W) - Body ground Always 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT POWER STEERING LINK ASSEMBLY (POWER STEERING MOTOR) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P43-3 (U) - P43-1 (V) Always Below 1 ohms P43-1 (V) - P43-2 (W) Always Below 1 ohms P43-2 (W) - P43-3 (U) Always Below 1 ohms NOTE: If replacing the power steering link assembly, clear the rotation angle sensor calibration value, initialize the rotation angle sensor value, and calibrate the torque sensor zero point (See «CALIBRATION» ). If replacing the power steering ECU assembly, initialize the rotation angle sensor value and calibrate the torque sensor zero point (See «CALIBRATION» ). NG: REPLACE POWER STEERING LINK ASSEMBLY OK: REPLACE POWER STEERING ECU ASSEMBLY

The motor rotation angle sensor detects the motor rotation angle and sends this information to the power steering ECU assembly.

DTC DETECTION ITEM CHART

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1. CHECK POWER STEERING EARTH WIRE (BETWEEN POWER STEERING LINK ASSEMBLY AND BODY GROUND) Check the installation condition of the power steering earth wire connected to the power steering link assembly. OK: The power steering earth wire is securely installed to the power steering link assembly and body ground. NG: REINSTALL POWER STEERING EARTH WIRE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (BETWEEN ECU ASSEMBLY AND MOTOR ROTATION ANGLE SENSOR) Disconnect the R25 connector from the power steering link assembly. Disconnect the P42 connector from the power steering ECU assembly. Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition R25-1 (RZSN) - P42-4 (RZSN) Always Below 1 ohms R25-2 (RZG) - P42-13 (RZG) Always Below 1 ohms R25-3 (RZV) - P42-2 (RZV) Always Below 1 ohms R25-4 (RZCS) - P42-3 (RZCS) Always Below 1 ohms R25-1 (RZSN) - Body ground Always 10 kohms or higher R25-2 (RZG) - Body ground Always 10 kohms or higher R25-3 (RZV) - Body ground Always 10 kohms or higher R25-4 (RZCS) - Body ground Always 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT POWER STEERING LINK ASSEMBLY (MOTOR ROTATION ANGLE SENSOR) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition R25-1 (RZSN) - R25-2 (RZG) Always 50 to 140 ohms R25-3 (RZV) - R25-2 (RZG) Always 50 to 140 ohms R25-4 (RZCS) - R25-2 (RZG) Always 15 to 45 ohms NOTE: If replacing the power steering link assembly, clear the rotation angle sensor calibration value, initialize the rotation angle sensor value, and calibrate the torque sensor zero point (See «CALIBRATION» ) NG: REPLACE POWER STEERING LINK ASSEMBLY OK: Go to next step
4. REPLACE POWER STEERING ECU ASSEMBLY Replace the power steering ECU assembly (See «POWER STEERING ECU» ). NEXT: Go to next step
5. INITIALIZE ROTATION ANGLE SENSOR VALUE AND CALIBRATE TORQUE SENSOR ZERO POINT Initialize the rotation angle sensor value and calibrate the torque sensor zero point (See «CALIBRATION» ). NEXT: Go to next step
6. RECONFIRM DTC Check for DTCs (See «DTC CHECK / CLEAR» ). Is DTC C1528 output? OK: DTC is not output. NOTE: If replacing the power steering link assembly, clear the rotation angle sensor calibration value, initialize the rotation angle sensor value, and calibrate the torque sensor zero point (See «CALIBRATION» ) NG: REPLACE POWER STEERING LINK ASSEMBLY OK: END

If the power steering ECU assembly detects these DTCs, it will shut off the motor relay circuit (built into the power steering ECU assembly) and stop power assistance. However, power assistance continue if DTC C1533 or C1534 is output.

DTC DETECTION ITEM CHART

The power steering ECU assembly receives vehicle speed signals from the skid control ECU via CAN communication. The ECU provides appropriate assisting force in accordance with the vehicle speed, based on the signals.

If the ECU detects this DTC, it adjusts the amount of power assistance for a speed of 100 km/h (62 mph) and continues the system control.

DTC TROUBLE DETECTION ITEM CHART

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If the power steering ECU assembly determines that there is a malfunction in the IG circuit inside the ECU, it will output this DTC. This DTC is not output when there is an open circuit in the wire harness connected to terminal IG or a battery voltage drop.

DTC TROUBLE DETECTION ITEM CHART

The power steering converter is activated and stopped by the power steering ECU assembly. This converter reduces the voltage supplied from the hybrid vehicle battery to 42 V and outputs the voltage as a power source for the power steering motor.

DTC TROUBLE DETECTION ITEM CHART

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Terminal +B of the power steering ECU assembly receives power from the battery and then provides power to the power steering converter and ignition off circuit.

(or The power steering ECU assembly receives power for the power steering converter and ignition off circuit from the battery via terminal +B.)

DTC TROUBLE DETECTION ITEM CHART

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1. CHECK HARNESS AND CONNECTOR Disconnect the P41 connector from the power steering ECU assembly. Measure the voltage according to the value in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P41-6 (+B) - P41-5 (PGND) Always 10 to 14 V NOTE: If replacing the power steering ECU assembly, initialize the rotation angle sensor value and calibrate the torque sensor zero point (See «CALIBRATION» ). NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE POWER STEERING ECU ASSEMBLY

The power steering ECU assembly outputs this DTC when it determines that assist map is not written in the ECU.

HINT

The assist map is data written in the power steering ECU assembly to control the degree of assistance.

The assist map is selected based on the vehicle's specified communication data (designation and grade package information).

DTC DETECTION ITEM CHART

The power steering ECU assembly receives signals from the HV control ECU, skid control ECU, and steering control ECU via CAN communication.

DTC DETECTION ITEM CHART

HINT

1. When two or more DTCs starting with "U" are output simultaneously, inspect the connectors and wire harness of each ECU.
2. If the power steering ECU assembly detects DTC U0121 only, it adjusts the amount of power assistance for a speed of 100 km/h (62 mph) and continues system control.

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The troubleshooting procedure for a situation in which no DTCs are output but the P/S warning light is always on is specified here. The P/S warning light remains on when there is an open in the IG circuit inputting power source voltage to the power steering ECU assembly.

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1. CHECK HARNESS AND CONNECTOR Check the indication condition of the P/S warning light while by wiggling the power steering ECU assembly connector and wire harness up and down, and then right and left. OK: P/S warning light indication condition does not change. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT CAN COMMUNICATION SYSTEM Using the intelligent tester, check for DTCs and confirm that there are no problems in the CAN communication system (See «DIAGNOSIS SYSTEM» ). OK: DTCs are not output. NG: GO TO «CAN COMMUNICATION SYSTEM» OK: Go to next step
3. INSPECT MULTIPLEX COMMUNICATION SYSTEM (BEAN) Using the intelligent tester, check for DTCs and confirm that there are no problems in the multiplex communication system (BEAN) (See «DTC CHECK / CLEAR» ). OK: DTCs are not output. NG: GO TO «MULTIPLEX COMMUNICATION SYSTEM (BEAN)» OK: Go to next step
4. INSPECT FUSE (ECU-IG No.1) Remove the ECU-IG No.1 fuse from the instrument panel J/B LH. Check for continuity of the ECU-IG No.1 fuse. OK: Continuity NG: REPLACE FUSE OK: Go to next step
5. INSPECT POWER STEERING ECU ASSEMBLY Disconnect the P41 connector from the power steering ECU assembly. Measure the voltage according to the value(s) in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P41-9 (IG) - P41-5 (PGND) Ignition switch on 10 to 14 V OK: GO TO step 7 NG: Go to next step
6. CHECK HARNESS AND CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND BODY GROUND) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P41-5 (PGND) - Body ground Always Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND BATTERY)
7. REPLACE POWER STEERING ECU ASSEMBLY Replace the power steering ECU assembly (See «POWER STEERING ECU» ). NOTE: After replacing the power steering ECU assembly, initialize the rotation angle sensor value and calibrate the torque sensor zero point (See «CALIBRATION» ). NEXT: Go to next step
8. CHECK P/S WARNING LIGHT Check the P/S warning light status on the combination meter. Standard: The P/S warning light is off. OK: END NG: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

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1. PLACE FRONT WHEELS FACING STRAIGHT AHEAD
2. SEPARATE CABLE FROM NEGATIVE BATTERY TERMINAL (See «AIRBAG SYSTEM»(/lexus/rx/ii-2006-2009/remont/airbag/#supplemental-restraint-system) )
3. REMOVE FRONT WHEELS
4. REMOVE ENGINE UNDER C0 VER NO.2
5. SEPARATE FRONT STABILIZER LINK ASSEMBLY LH (See «REMOVAL» )
6. SEPARATE FRONT STABILIZER LINK ASSEMBLY RH HINT: Perform the same procedure as for the LH side.
7. SEPARATE STEERING INTERMEDIATE SHAFT SUB-ASSEMBLY Fix the steering wheel with the seat belt in order to prevent rotation. HINT: This operation is useful to prevent damage to the spiral cable. Loosen the bolt (A) and remove the clamp from the steering column hole shield. Loosen the bolt (B). HINT: Do not remove the bolt (B). Remove the bolt, and then slide the steering intermediate shaft sub-assembly. NOTE: Do not separate the steering intermediate shaft sub-assembly. Put matchmarks on the steering intermediate shaft sub-assembly and the power steering link assembly. Separate the steering intermediate shaft sub-assembly from the power steering link assembly.
8. SEPARATE TIE ROD ASSEMBLY LH Remove the cotter pin and the nut. Using SST, separate the tie rod assembly LH from the steering knuckle. SST 09628-00011 NOTE: Hang SST with a string, etc. to prevent it from falling. Do not damage the front disc brake dust cover. Do not damage the ball joint dust cover. Do not damage the steering knuckle.
9. SEPARATE TIE ROD ASSEMBLY RH SST 09628-00011 HINT: Perform the same procedure as for the LH side.
10. REMOVE ENGINE ASSEMBLY WITH TRANSAXLE HINT: Refer to the instructions for removal of the engine assembly (See «REMOVAL»(/lexus/rx/ii-2006-2009/remont/mechanical/#engine-mechanical) ).
11. REMOVE POWER STEERING LINK ASSEMBLY Remove the 2 bolts, 2 nuts, and the power steering link assembly from the front frame assembly.

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1. FIX POWER STEERING LINK ASSEMBLY Using SST, secure the power steering link assembly. SST 09612-00012 HINT: Tape the SST before use.
2. REMOVE TIE ROD ASSEMBLY LH Put matchmarks on the tie rod assembly LH and the steering rack end sub-assembly. Loosen the lock nut, and remove the tie rod assembly LH and the lock nut.
3. REMOVE TIE ROD ASSEMBLY RH HINT: Perform the same procedure as for the LH side.
4. REMOVE STEERING RACK BOOT CLIP Using pliers, remove the 2 steering rack boot clips.
5. REMOVE STEERING RACK BOOT NO.2 CLAMP Using pliers and a screwdriver, remove the steering rack boot No.2 clamp as shown in the illustration. NOTE: Be careful not to damage the boot.
6. REMOVE STEERING RACK BOOT NO.1 CLAMP HINT: Perform the same procedure as for the steering rack boot No.2 clamp.
7. REMOVE STEERING RACK BOOT NO.2 Remove the steering rack boot No.2.
8. REMOVE STEERING RACK BOOT NO.1 HINT: Perform the same procedure as for the steering rack boot No.2.
9. REMOVE STEERING RACK END SUB-ASSEMBLY Using a screwdriver and a hammer, unstake the RH and LH claw washers. NOTE: Avoid any impact to the steering rack. Using SST, remove the steering rack end sub-assembly (LH side) and the claw washer. SST 09922-10010 NOTE: Use SST 09922-10010 following the direction shown in the illustration. Using SST, remove the steering rack end sub-assembly (RH side) and the claw washer. SST 09922-10010 NOTE: Use SST 09922-10010 following the direction shown in the illustration. HINT: Using SST, hold the rack and remove the steering rack end sub-assembly.

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1. INSPECT TIE ROD ASSEMBLY LH Secure the tie rod assembly LH in a vise. Install the nut to the stud bolt. Flip the ball joint back and forth 5 times or more. Using a torque wrench, turn the nut continuously at a rate of 3 to 5 seconds per turn and take the torque reading on the 5th turn. Turning torque: 0.49 to 3.43 N*m (5.0 to 35 kgf*cm, 4.3 to 30.4 in.*lbf) If turning torque is not within the specified range, replace the tie rod assembly LH.
2. INSPECT TIE ROD ASSEMBLY RH HINT: Perform the same procedure as for the LH side.
3. INSPECT TOTAL PRELOAD Temporarily install the left and right steering rack ends to prevent steering rack over stroke. Using SST and a torque wrench, inspect total preload. SST 09616-00011 Preload (turning): 1.0 to 2.0 N*m (10.2 to 20.4 kgf*cm, 8.9 to 17.7 in.*lbf) If turning torque is not as specified, replace the power steering link assembly.
4. INSPECT POWER STEERING LINK ASSEMBLY (TORQUE SENSOR) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P44-1 (INCS) - P44-7 (TQG2) Always 90 to 170 ohms P44-2 (INSN) - P44-7 (TQG2) Always 300 to 430 ohms P44-4 (TRQV) - P44-8 (TRQG1) Always 4 to 14 ohms P44-5 (OUCS) - P44-7 (TQ62) Always 90 to 170 ohms P44-6 (OUSN) - P44-7 (TQG2) Always 300 to 430 ohms
5. INSPECT POWER STEERING LINK ASSEMBLY (POWER STEERING MOTOR) Measure the resistance according to the value(s) in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester connection (Symbols) Condition Specified condition P43-3 (U) - P43-1 (V) Always Below 1 ohms P43-1 (V) - P43-2 (W) Always Below 1 ohms P43-2 (W) - P43-3 (U) Always Below 1 ohms

See also:
• AIRBAG SYSTEM
• DTC CHECK / CLEAR
• REMOVAL
• REMOVAL