Description
The EPS (Electric Power Steering) is a column-assist type system that uses an electric motor to assist the steering force, and operates independent of engine operation.
The EPS control module controls the motor operation according to information received from each sensor.
This results in a more precise and timely control of steering assist compared to a conventional engine-driven hydraulic system.
The components (torque sensor, fail-safe relay, etc.) of the EPS system are located inside the steering column & EPS unit assembly. The steering column & EPS unit assembly may only be replaced as an entire assembly, and should never be disassembled or inspected.
Notes With Regard To Diagnosis
| Trouble factor | Check item | Trouble symptom | Explanation | Note |
|---|---|---|---|---|
| Drop, impact, and overload | Motor | Abnormal noise | Visible or invisible damage can occur. The steering wheel could pull to one side by using the dropped parts. Precise parts of motor/ECU are sensitive to vibration and impact. Overload can cause unexpected damage | Do not use the impacted EPS. Do not overload each parts. |
| ECU | Circuit damage Wrong welding point Broken PCB Damaged precise parts | |||
| Torque sensor | Insufficient steering effort | Overload to INPUT shaft can cause malfunction of the torque sensor | Do not impact the connecting parts (When inserting and torquing) Use the specified tool to remove the steering wheel. (Do not hammer on it) Do not use the impacted EPS | |
| Shaft | Insufficient steering effort (Uneven between LH and RH) | Do not use the impacted EPS | ||
| Pull/Dent | Harness | Malfunction impossible power operation Malfunction of EPS | Disconnection between harness connecting portion and harness | Do not overload the harness |
| Abnormal storage temperature | Motor/ECU | Abnormal steering effort by improper operation of the motor/ECU | Waterproof at the normal condition Even a little moisture can cause malfunction of the precise parts of the motor/ECU | Maintain normal temperature and proper moisture, while storing Avoid drowning |
TROUBLE SYMPTOM CHART
- Do not impact the electronic parts, if they are dropped or impacted, replace them with new ones.
- Avoid heat and moisture to the electronic parts.
- Do not contact the connect terminal to avoid deformation and static electricity.
- Do not impact the motor and torque sensor parts, if they are dropped or impacted, replace them with new ones.
- The connector should be disconnected or connected with IG OFF.
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- Disconnect the battery negative cable from the battery and then wait for at least 30 seconds.
- Turn the steering wheel so that the front wheels can face straight ahead. Mark steering wheel for alignment purposes.
- Remove the airbag module. (Refer to «AIRBAG MODULE (RESTRAINTS - ADVANCED)»(ref-362244) or «AIRBAG MODULE (RESTRAINTS - DEPOWERED)»(ref-362249) )
- Loosen the steering wheel lock nut.
- Remove the steering wheel from the steering column shaft by using a SST (09561-11001). CAUTION: Do not hammer on the steering wheel to remove it; it may damage the steering column.
- Remove the steering column upper (A) and lower shroud (B).
- Remove the clock spring.
- Loosen the screws and then remove the multifunction switches.
- Remove the lower crash pad. (For Coupe, refer to «CRASH PAD»(ref-362224-S30236245892010060400000) . For Sedan, refer to «CRASH PAD»(ref-362245-S13817783762010060400000) .)
- Loosen the bolt and then disconnect the universal joint assembly from the pinion of the steering gear box. Tightening torque: 30 ~ 35N.m (3.0 ~ 3.5kgf.m, 22 ~ 25lb-ft) CAUTION: Keep the vehicle in the neutral-range to prevent damage to the clock spring inner cable while handling the steering wheel.
- Disconnect all connectors connected the steering column.
- Remove the steering column & EPS unit assembly by loosening the mounting bolts and nuts. Tightening torque: 13 ~ 18N.m (1.3 ~ 1.8kgf.m, 9 ~ 13lb-ft)
- Installation is the reverse of the removal. CAUTION: When installing the clock spring, refer to «DRIVER AIRBAG (DAB) MODULE AND CLOCK SPRING»(ref-362244-S17122052172010060400000) to prevent the damage of clock spring inner cable.