Contents Wiring diagrams Section: Manual & Power Steering All sections

Steering Control System: Diagnosis Lexus ES XV30

Manual & Power Steering 12 illustrations ~735 words

PROBLEM SYMPTOMS TABLE

Note. Use the table below to help you find the cause of the problem. The numbers indicate the priority of the likely cause of the problem. Check each part in the order shown. If necessary, repair or replace these parts.

Symptom/Suspect AreaRefer To
Hard Steering
Tires (Improperly Inflated)(1)
Power Steering Fluid Level (Low)Step 3 under ON-VEHICLE INSPECTION
Drive Belt(1)
Front Wheel Alignment (Incorrect)ALIGNMENT SPECIFICATIONS & PROCEDURES
Steering System Joints (Worn)(2)
Suspension Arm Ball Joints (Worn)LOWER BALL JOINT ASSEMBLY
Steering Column (Binding)(2)
Power Steering GearOVERHAUL under RACK & PINION POWER STEERING GEAR ASSEMBLY
Power Steering PumpPOWER STEERING SYSTEM
Poor Return
Tires (Improperly Inflated)(1)
Front Wheel Alignment (Incorrect)ALIGNMENT SPECIFICATIONS & PROCEDURES
Steering Column (Binding)(2)
Power Steering GearOVERHAUL under RACK & PINION POWER STEERING GEAR ASSEMBLY
Excessive Play
Steering System Joints (Worn)(2)
Suspension Arm Ball Joints (Worn)LOWER BALL JOINT ASSEMBLY
Intermediate Shaft, Universal Joint, Sliding Yoke (Worn)(2)
Front Wheel Bearing (Worn)BEARING BACKLASH & AXLE HUB DEVIATION
Power Steering GearOVERHAUL under RACK & PINION POWER STEERING GEAR ASSEMBLY
Power Steering PumpVANE PUMP ASSEMBLY
Abnormal Noise
Power Steering Fluid Level (Low)Step 3 under ON-VEHICLE INSPECTION
Steering Systems Joints (Worn)(2)
Power Steering GearOVERHAUL under RACK & PINION POWER STEERING GEAR ASSEMBLY
(1) Inspect and adjust as necessary. (2) Inspect and repair/replace as necessary.
(1)Inspect and adjust as necessary.
(2)Inspect and repair/replace as necessary.

Problem Symptoms

Scheme 2

Scheme 2: ON-VEHICLE INSPECTION

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Scheme 4

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Scheme 5

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Scheme 6

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Scheme 7

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Scheme 9

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Scheme 10

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Scheme 11

Scheme 11
  1. Inspect drive belt. Visually check the belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt. NOTE: Cracks on the rib side of a belt are considered acceptable. If the missing chunks from the ribs are found on the belt, it should be replaced.
  2. Bleed power steering system. Check the fluid level. Jack up the front of the vehicle and support it with the stands. Turn the steering wheel. With the engine stopped, turn the wheel slowly from lock to lock several times. Lower the vehicle. Start the engine. Run the engine at idle for a few minutes. Turn the steering wheel. With the engine idling, turn the wheel to left or right full lock position and keep it there for 2-3 seconds, then turn the wheel to the opposite full lock position and keep it there for 2-3 seconds. Repeat step 1 several times. Stop the engine. Check for forming or emulsification. Especially, if the system has to be bled twice because of foaming or emulsification, check for fluid leaks in the system. Check the power steering fluid level.
  3. Check fluid level. Keep the vehicle level. With the engine stopped, check the fluid level in the oil reservoir. If necessary, add fluid. Fluid: ATF DEXRON(R) II or III NOTE: Check that the fluid level is within the HOT LEVEL range on the reservoir cap. If the fluid is cold, check that it is within the COLD LEVEL range. Start the engine and run it at idle. Turn the steering wheel from lock to lock several times to raise fluid temperature. Fluid Temperature: 75-80°C (167-176°F) Check for foaming or emulsification. If foaming or emulsification is identified, bleed the power steering system. With the engine idling, measure the fluid level in the oil reservoir. Stop the engine. Wait a few minutes and remeasure the fluid level in the oil reservoir. Maximum Fluid Level Rise: 5 mm (0.20 in.) If a problem is found, bleed the power steering system. Check the fluid level.
  4. Check Steering Fluid Pressure: Disconnect the pressure feed tube from the power steering gear. See «RACK & PINION POWER STEERING GEAR ASSEMBLY»(ref-175163-S25946908292005041800000) . Connect SST, as shown in the illustration. SST 09640-10010 (09641-01010, 09641-01020, 09641-01030) NOTE: Check that the valve of the SST is in the open position. Bleed the power steering system. Start the engine and run it at idle. Turn the steering wheel from lock to lock several times to raise fluid temperature. Fluid Temperature: 75-80°C (167-176°F) With the engine idling, close the valve of the SST and observe the reading on the SST. Fluid Pressure: 7800-8300 kPa (80-85 kgf/cm 2 , 1138-1209 psi NOTE: Do not keep the valve closed for more than 10 seconds. Do not let the fluid temperature become too high. With the engine idling, open the valve fully. Measure the fluid pressure at engine speeds of 1000 RPM and 3000 RPM. Fluid Pressure Difference: 490 kPa (5 kgf/cm 2 , 71 psi) or less. NOTE: Do not turn the steering wheel. With the engine idling and valve fully opened, turn the steering wheel to full lock position. Fluid Pressure: 7800-8300 kPa (80-85 kgf/cm 2 , 1138-1209 psi) NOTE: Do not maintain lock position for more than 10 seconds. Do not let the fluid temperature become too high. Disconnect the SST. SST 09640-10010 (09641-01010, 09641-01020, 09641-01030) Connect the pressure feed tube to the power steering gear. See «RACK & PINION POWER STEERING GEAR ASSEMBLY»(ref-175163-S25946908292005041800000) . Bleed the power steering system.
  5. Check steering effort Center the steering wheel assembly. Remove the horn button assembly. See OVERHAUL . Start the engine and run it at idle. Measure the steering effort in both directions. Steering Effort (Reference): 6 N.m (60 kgf.cm, 53 in.lbf) or less NOTE: Take the tire type, pressure and contact surface into consideration before making your diagnosis. Install the steering wheel assembly set nut. Torque: 50 N.m (510 kgf.cm, 37 ft.lbf) Install the horn button assembly. See OVERHAUL .

Scheme 12

Scheme 12: COMPONENTS

Scheme 13

Scheme 13