Symptom Related Diagnostic Procedures

Symptom Troubleshooting Index





Part 1 of 2





Part 2 of 2

Find the symptom in the chart and do the related procedures in the order listed until you find the cause.

Symptom Troubleshooting
Hard Steering
1. Check the power assist.
Is the power assist more than 29 N (3.0 kgf, 6.6 ft. lbs.)?
YES - Go to step 2.
NO - Power assist is OK.
2. Measure steady-state fluid pressure from the pump at idle with T/N 07406-0010001, with T/N 07406-001000A.
Is the pressure 1,500 kPa (15 kgf/cm2, 213 psi) or less?
YES - Go to step 3.
NO - Go to step 7.
3. Measure the pump relief pressure at idle with T/N 07406-0010001, with T/N 07406-001000A.
Is the pressure 7,200 - 7,800 kPa (73 - 80 kgf/cm2, 1,040 - 1,140 psi) or less?
YES - Go to step 4.
NO - Go to step 8.
4. With 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 ft. lbs.) of each other?
YES - Go to step 5.
NO - Go to step 9.
5. Measure the fluid pressure with T/N 07406-0010001, with T/N 07406-001000A 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 7,200 - 7,800 kPa (73 - 80 kgf/cm2, 1,040 - 1,140 psi) or less?
YES - Go to step 6.
NO - Faulty gearbox.
6. Adjust the rack guide, and retest.
Is the steering OK?
YES - Repair is completed.
NO - Faulty gearbox.
7. Check for the supply and return lines between the pump and the gearbox for clogging and deformation.
Are the lines clogged or deformed?
YES - Repair or replace the lines.
NO - Faulty valve body unit.
8. Check the flow control valve for smooth movement and leaks.
Is the flow control valve OK?
YES - Faulty pump assembly.
NO - Faulty flow control valve.
9. Check the cylinder lines A and B for deformation.
Are the A or B lines deformed?
YES - Replace the lines.
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.
NO - Faulty valve body unit.