Nissan Versa Sedan Service ManualSteering » Steering control system (STC) » Precautions
Service Notice and Precautions for EPS System
Service Notice and Precautions for EPS System
- Check the following item when performing the trouble diagnosis.
- Check any possible causes by interviewing the symptom and it′s condition from the customer if any malfunction, such as EPS warning lamp is turned ON, occurs.
- Check if air pressure and size of tires are proper, the specified part is used for the steering wheel, and control unit is genuine part.
- Check if the connection of steering column assembly and steering gear assembly is proper (there is not looseness of bolts, damage of rods, boots or sealants, and leakage of grease, etc.).
- Check if the wheel alignment is adjusted properly.
- Check if there is any damage or modification to suspension or body resulting in increased weight or altered ground clearance.
- Check if installation conditions of each link and suspension are proper.
- Check if the battery voltage is proper.
- Check connection conditions of each connector are proper.
- Before connecting or disconnecting the EPS control unit harness connector, turn ignition switch "OFF" and disconnect battery ground cable. Because battery voltage is applied to EPS control unit even if ignition switch is turned "OFF".
- When connecting or disconnecting pin connectors into or from EPS control unit, take care not to damage pin terminals (bend or break).
- When connecting pin connectors, make sure that there are no bends or breaks on EPS control unit pin terminal.
- During quick steering, rasping noise may be heard from around the steering wheel. This is not a malfunction. The noise is an operating noise of the EPS system under normal conditions. If the rasping noise occurs during slow steering, this may not be an operating noise of the system. In this case, it is necessary to find out the location of the noise and repair, if necessary.
SYSTEM DESCRIPTION
COMPONENT PARTS
Component Parts Location
1. ABS actuator and electric unit (control unit) 2. ECM 3. Combination meter 4. EPS motor 5. Reduction gear 6. EPS control unit 7. Torque sensor A. Steering column assembly (view with removed from vehicle) B. EPS warning lamp (In combination meter)
Component Description
| Components parts | Reference |
| EPS control unit | STC "EPS Control Unit" |
| EPS motor | STC "EPS Motor" |
| Torque sensor | STC "Torque Sensor" |
| Reduction gear | STC "Reduction Gear" |
| EPS warning lamp | STC "EPS SYSTEM : System Description" |
| ECM | - Transmits mainly the following signals to EPS control unit via
CAN communication. - Engine status signal |
| ABS actuator and electric unit (control unit) | - Transmits mainly the following signal to EPS control unit via
CAN communication. - Vehicle speed signal (ABS) |
| Combination meter | - Transmits mainly the following signal to EPS control unit via
CAN communication. - Vehicle speed signal (METER) - Turns ON the EPS warning lamp according to the signal from EPS control unit via CAN communication. |
EPS Control Unit
- EPS control unit performs an arithmetical operation on data, such as steering wheel turning force (sensor signal) from the torque sensor, vehicle speed signal, etc. Then it generates an optimum assist torque signal to the EPS motor according to the driving condition.
- EPS control unit decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control).
EPS Motor
EPS motor provides the assist torque by the control signal from EPS control unit.
Torque Sensor
Torque sensor detects the steering torque, and transmit the signal to EPS control unit.
Reduction Gear
Reduction gear increases the assist torque provided from EPS motor with worm gears, and outputs to the column shaft.
SYSTEM
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT PRE-TENSIONER"
Service Notice and Precautions for EPS System
Nissan Versa Sedan Service Manual
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