Electronic Power Steering (Eps): Diagnosis Mazda RX-8 I

Play Inspection

1. With the wheels in the straight-ahead position, start the engine.
2. Turn the steering wheel to the left and right gently, and verify that the steering wheel play is within the specification. Play 0-30 mm {0-1.2 in}

Scheme 33

1. Move the steering wheel toward the shaft and in four right angle directions to inspect for looseness and play. If there is any malfunction, inspect the following, and repair or replace the applicable part. Column bearing wear Looseness of the steering wheel installation part Looseness of the column installed part Excessive play of the steering shaft joint Excessive play of the steering gear

Steering Wheel Effort Inspection

1. Verify that the equipped tire size and tire air pressure is as specified.
2. With the vehicle on a hard, level surface, put the wheels in the straight-ahead position. WARNING: Handling the air bag module improperly can accidentally deploy the air bag module, which may seriously injure you. Read the service warnings before handling the air bag module. (See «AIR BAG SAFETY PRECAUTIONS»(ref-170350-S18012488582005011000000) .)
3. Remove the air bag module.
4. Start the engine and idle it.
5. Verify that the EPS warning light does not illuminate.
6. Inspect the steering wheel effort using a torque wrench.

1. If it exceeds the reference value, adjust the steering gear and linkage. (See «STEERING GEAR AND LINKAGE ADJUSTMENT»(ref-178305-S22540871672005061400000) .)

Reference value

5.0 N.m {50 kgf.cm, 44 in.lbf} or less

Scheme 34

Note. To determine whether the steering effort is satisfactory or not, perform the inspection on another vehicle of the same model and under the same conditions, and compare the results. The steering wheel effort varies with conditions indicated below. Road conditions: such as dry or wet, asphalt or concrete Tire conditions: such as brand, wear, and tire air pressure

Tie Rod Inspection

1. Inspect for damage, bending and excessive play. If there is any malfunction, replace the steering gear and linkage.
2. Swing the ball joint 5 times .
3. Measure the swing torque using a pull scale.

1. It is exceeds the specification, replace the steering gear and linkage.

Standard swing torque

0.68-2.45 N.m

{7.0-24.9 kgf.cm, 6.1-21.6 in.lbf}

pull scale reading

6.8-24.5 N {0.70-2.49 kgf, 1.53-5.50 lbf}

Scheme 35

Scheme 36

1. Disassemble in the order indicated in (Scheme 36).
2. Assemble in the reverse order of disassembly.

Scheme 37

1. Place alignment marks as shown in the figure for proper installation.
2. Remove the tie-rod end.

Scheme 38

1. Press the mounting rubber out from the gear housing using the SSTs and a press.

Scheme 39

Scheme 40

1. Apply soapy water to the rubber part of the mounting rubber.
2. Press the mounting rubber until the mounting rubber end comes out completely from the gear housing using the SSTs and a press.
3. Reverse the gear housing, then press the mounting rubber until the mounting rubber end comes out completely from the other side. At this time, verify that the mounting rubber and steel pipe are aligned.

Scheme 41

1. Crimp the boot band using the SST.
2. Verify that the crimping clearance A is within the specification. If crimping clearance A exceeds the specification, reduce SST clearance, and crimp the boot band again. If crimping clearance A is less than the specification, increase SST clearance, and crimp a new boot band. Standard clearance A 2-3 mm {0.08-0.11 in}
3. Rotate the boot by hand and verify that it is securely installed to the boot band.

Scheme 42

1. Wipe off the old grease from the ball stud.
2. Fill the inside of the new dust boot with grease.
3. Install the dust boot on the ball joint.
4. Install the clip using the SST.
5. Verify that the clip is installed securely to the groove.
6. Wipe off any excess grease.

Scheme 43

Scheme 44

Scheme 45

Scheme 46

1. Remove the locknut using the SST.
2. Apply sealant to the threads of the adjustment cover.
3. Tighten the adjustment cover to 20-29 N.m {2.1-2.9 kgf.cm, 15-21 in.lbf}.
4. After swinging the steering rack left and right 10 times, tighten the adjustment cover again to 5.8 N.m {59 kgf.cm, 51 in.lbf}.
5. Loosen the adjustment cover 10-20°.
6. Lock the adjustment cover against rotation and tighten the locknut using the SST. Tightening torque 20-29 N.m {2.1-2.9 kgf.cm, 15-21 in.lbf}
7. Measure the pinion shaft rotational torque using the SST and a pull scale. If not within the specification, repeat from Steps 1 - 6 . Standard rotational torque 1.2-2.0 N.m {13-20 kgf.cm, 11-17 in.lbf} Pull scale reading 11.2-20.0 N {1.15-2.03 kgf, 2.52-4.48 lbf}

Scheme 47

1. Measure the resistance between torque sensor connector terminals A and B, and B and C. If there is any malfunction, replace the steering gear and linkage. Standard A-B: 12-15 ohms B-C: 12-15 ohms

EPS CONTROL MODULE INSPECTION

1. Remove the engine cover, battery cover, and PCM cover.
2. Remove the PCM and the EPS control module. (See «EPS CONTROL MODULE REMOVAL/INSTALLATION»(ref-178305-S09505822102005061400000) .)
3. Connect the PCM and EPS control module connectors.
4. Attach the tester lead to the underside of the control module connector and inspect the voltage and continuity according to the Terminal Voltage Table (Reference) indicated in the table. See «TERMINAL VOLTAGE TABLE (REFERENCE)»(ref-178305-S09225781672005061400000) . NOTE: When inspecting the torque sensor and EPS motor for continuity, turn the ignition switch off and inspect with the connectors for the EPS control module, torque sensor, and EPS motor disconnected.

Scheme 48

Scheme 49

Scheme 50

Scheme 51

1. Set the front wheels in the straight-ahead position. (Steering wheel is within 45° to the left or right of center position.)
2. Jack up both front tires so that there is no weight on them.
3. Lower the jack until the front tires touch the ground. At this time, be careful not to touch the tires or the steering wheel.
4. Connect the WDS or equivalent to the DLC-2.
5. Set to neutral by selecting the TRQ_S_CAL active command mode function.
6. After setting to neutral, start the engine, rotate the steering wheel slowly in both directions within a range of 90°, and verify that the steering force does not differ in either directions. If the steering force is different in either direction, inspect the power steering system following a separate troubleshooting procedure. (See «NO. 3 POWER ASSIST DIFFERS BETWEEN RIGHT & LEFT»(ref-178303-S15444651352005061400000) .)