Description
EPS (Electric power steering, Column assist type) system uses an electric motor to assist the steering force and it is an engine operation independent steering system.
EPS control module controls the motor operation according to information received from the each sensor and CAN (Controller Area Network)
resulting in a more precise and timely control of steering assist than conventional engine-driven hydraulic systems.
Components (Steering Angle Sensor, Torque Sensor, Fail-safe relay, etc.) of the EPS system are located inside the steering column. EPS unit assembly, steering column, and EPS unit assembly must not be disassembled for inspection. They must be replaced if necessary.
Note With Regard to diagnosis
| Trouble factor | Check item | Trouble symptom | Explanation | Note |
|---|---|---|---|---|
| Drop, impact, and overload | Motor | Abnormal noise | Visible or unvisable 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 | Keep the 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.
Scheme 1
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| Type | Pin No | Description |
|---|---|---|
| Battery | 1 | Battery |
| 2 | Battery + | |
| Vehicle | 1 | IGN |
| 2 | ||
| 3 | ||
| 4 | ||
| 5 | ||
| 6 | ||
| 7 | High_CAN | |
| 8 | Low_CAN |
PIN DESCRIPTION CHART
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Scheme 21
- 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.
- Push the pin (A) and then disconnect the airbag module from the steering wheel.
- Disconnect the airbag module connector (A) & horn connector (B) and then remove the airbag module from the steering wheel.
- Disconnect the lock nut (A) & connector (B) and the remove the steering wheel from the steering column shaft. Tightening torque: 39.2 ~ 49.0 N.m (4.0 ~ 5.0kgf.m, 28.9 ~ 36.2 lb-ft) CAUTION: Do not hammer on the steering wheel to remove it may damage the steering column.
- Loosen the screw and then remove the steering column upper (A) and lower (B) shroud.
- Disconnect the connector and then remove the clock spring (A).
- Disconnect the connector & screw and then remove the multifunction switches (A).
- Remove the crash lower panel.
- Loosen the bolt (A) and then disconnect the universal joint assembly from the pinion of the steering gear box. Tightening torque: 29.4 ~ 34.3 N.m (3.0 ~ 3.5kgf.m, 21.7 ~ 25.7 lb-ft) CAUTION: Do not use the bolt again.
- Loosen the screw and then remove the shower duct (A).
- Disconnect all connectors connected to the steering column.
- Remove the steering column by loosening the mounting bolts and nuts. Tightening torque: 12.7 ~ 17.7 N.m (1.3 ~ 1.8kgf.m, 9.4 ~ 13.0 lb-ft)
- Installation is the reverse of the removal.
- Compensate the steering angle sensor after replacing the steering column.
Scheme 22
- Loosen the bolt (A) and then disconnect the universal joint assembly from the steering column assembly.
- Reassembly is the reverse of the disassembly.
Scheme 23
- Make a groove on the head of special bolts (A) by a punch.
- Loosen the special bolt using a screw driver and then remove the key lock assembly from the steering column assembly.
- Reassembly is the reverse of the disassembly.