Hydraulic Power Steering Symptom Troubleshooting

Hydraulic Power Steering Symptom Troubleshooting

Hard Steering

NOTE:

- Compare to a known-good vehicle that is the same trim level.
- Check for suspension damage.
- Check the steering alignment.
- Check the tire condition and pressure.

1. Check the power assist Power Steering Assist Check.

Is the initial turning load more than 31 N (3.2 kgf,7.1 lbf)?

YES -

Go to step 2.

NO -

Power assist is OK at this time. Compare to a known-good vehicle.�

2. Connect the P/S joint adapter (pump), hose joint adapter, and P/S pressure gauge T/N 07406-0010001 Hydraulic Power Steering Pump Pressure Test With T/N 07406-0010001, T/N 07406-001000A, or T/N 07406-001A101 Hydraulic Power Steering Pump Pressure Test With T/N 07406-001000A Or T/N 07406-001A101 to the pump.

3. Measure steady-state fluid pressure from the pump at idle.

Is the pressure 1,470 kPa (15 kgf/cm2, 213 psi) or less?

YES -

Go to step 4.

NO -

Go to step 8.

4. Measure the pump relief pressure at idle.

Is the pressure 8,550-9,050 kPa (87.2-92.3 kgf/cm2, 1,240-1,313 psi) or more?

YES -

Go to step 5.

NO -

Replace the pump assembly Removal and Replacement.�

5. Using a spring scale, measure the power assist in both directions, to the left and to the right.

Are the two measurements within 5.0 N (0.51 kgf, 1.12 lbf) of each other?

YES -

Go to step 6.

NO -

Go to step 9.

6. Measure the fluid pressure with both pressure gauge valves open (if so equipped), while turning the steering wheel fully to the left and fully to the right.

Is the pressure 8,550-9,050 kPa (87.2-92.3 kgf/cm2, 1,240-1,313 psi) or less?

YES -

Go to step 7.

NO -

Faulty steering gearbox. Overhaul the steering gearbox Overhaul.�

7. Adjust the rack guide Adjustments, and retest.

Is the steering OK?

YES -

Repair is completed.�

NO -

Faulty steering gearbox. Overhaul the steering gearbox Overhaul.�

8. Check the outlet and return hoses and the lines between the pump and the steering gearbox for clogging and deformation.

Are the lines clogged or deformed?

YES -

Repair or replace the lines.�

NO -

Faulty valve body unit. Replace the valve body unit Overhaul.�

9. Check the cylinder lines for deformation Service and Repair.

Are any of the line(s) deformed?

YES -

Replace the deformed line.�

NO -

Go to step 10.

10. Check for a bent rack shaft or misadjusted rack guide (too tight).

Is the rack shaft bent or the rack guide adjusted too tight?

YES -

Replace the rack shaft, or readjust the rack guide preload.�

NO -

Faulty valve body unit. Replace the valve body unit Overhaul.�