What causes problems with the electric power steering system in a car?
Compared to the traditional hydraulic power steering system, the Electric Power Steering system has become an indispensable part of modern cars. EPS is lighter, more energy-efficient, and can provide more precise steering assistance through electronic control. However, despite the maturity of the electric power steering system technology, various problems related to it may still occur during vehicle use.
So, what exactly causes problems with the electric power steering in a car? This article will explore this issue in depth, analyzing the possible reasons and the working principles behind it.
What is the principle of the electric power steering system?
Before analyzing the problem, it is important to understand the basic principles of the power steering system. The EPS system provides steering assistance through an electric motor and an electronic control unit (ECU). Compared with traditional hydraulic steering, EPS does not require a complex hydraulic system, thereby reducing vulnerable parts such as hydraulic oil, pumps and pipes.
The core working mechanism of the electric power steering system includes the following key components:
1. Steering angle sensor: responsible for detecting the turning angle of the steering wheel and transmitting information to the electronic control unit (ECU)
2. Torque sensor: monitors the torque applied by the driver to the steering wheel to determine the amount of power required.
3. Motor: provides the necessary steering assistance according to the instructions of the ECU to help the driver turn the steering wheel.
4. Electronic Control Unit (ECU): responsible for analyzing the data sent by the sensor and determining the amount of power assistance based on factors such as driving conditions and vehicle speed.
5. Power system: provides power to the entire electric power steering, usually powered by the vehicle's battery.
The electric power steering system is based on the collaborative work of these electronic components to provide the driver with smooth and precise steering assistance. However, problems with any one component may cause the entire system to fail, thereby affecting the vehicle's steering performance.
What are the problems with the electric power steering system?
Electrical failure
Because the electric power steering system relies on electronic components for control, electrical failure is one of the main causes of problems. The power required for the EPS system is usually provided by the car battery, so it is closely related to the vehicle's electrical system. Electrical failures can come from a number of sources:
● Low battery voltage: If the car's battery voltage is too low, the electric power steering system may not receive enough power, resulting in insufficient power assistance or complete failure. Low voltage can be caused by an aging battery, a faulty generator, or poor wiring contact.
● Poor wiring contact: Due to constant vibration when the vehicle is driving, the circuit connections of the EPS system may become loose, resulting in poor circuit contact. If the connecting cables to the motor or ECU are loose or damaged, the system may not operate properly or even stop working completely.
● Fuse or relay failure: If the fuse or relay in the electric power steering system fails, the EPS system will also fail. The function of the fuse is to protect the system from damage caused by excessive current. Once the fuse blows, the EPS system will not function properly.
Motor failure
The motor is the core component that provides power assistance in the electric power steering. Over time, the motor may fail due to overuse, wear, or aging. Common motor failures include:
● Overheating problems: If the motor is under high load for a long time, it may overheat. This situation usually occurs when the vehicle is frequently turning or in extreme driving conditions, such as long-term low-speed steering or frequent stop-and-start processes. An overheated motor can cause the system to automatically shut down to prevent damage, resulting in steering failure.
● Internal motor damage: Damage to mechanical or electrical components inside the motor can also cause the electric power steering system to not work properly. These components include brushes, rotors, etc. When they wear or fail, the performance of the motor will be affected.
Electronic Control Unit (ECU) Failure
As the brain of the electric power steering system, the electronic control unit (ECU) plays a vital role in the entire steering process. The ECU receives data from sensors, determines the driver's steering intention, and controls the motor to provide appropriate power assistance. However, the ECU may also fail, causing the steering system to fail. Common causes of ECU failure include:
● Software problems: The vehicle's ECU operates through complex software algorithms. If there is a problem with the software or a program failure, it may cause the system to misjudge the need for power assistance, thereby affecting the accuracy of the steering assistance or completely failing.
● Hardware failure: The electronic components inside the ECU may be damaged by aging, moisture, overheating, or electromagnetic interference. Once the ECU has a hardware failure, the entire electric power steering will not work properly.
Sensor failure
The electric power steering relies on multiple sensors to detect information such as the vehicle's steering angle, torque, and speed. If the sensor fails, the system will not be able to obtain accurate data and will not be able to provide appropriate power assistance. Common sensor problems include:
● Torque sensor failure: The torque sensor is responsible for measuring the torque applied by the driver to the steering wheel. If this sensor fails, the system will not be able to correctly judge the driver's steering intention, which may result in insufficient power assistance or abnormally heavy steering.
● Steering angle sensor failure: The function of the steering angle sensor is to monitor the turning angle of the steering wheel. If this sensor cannot correctly feedback data, the electric power steering system may not be able to provide accurate steering assistance or may even fail completely.
Mechanical failure
Although the electric power steering mainly relies on electronic and electrical components, it still needs to work in conjunction with the vehicle's mechanical steering system. Failure of some mechanical components may also cause problems with the electric power steering. For example:
● Steering gear wear: Mechanical components of the steering system, such as the steering gear, if severely worn, will cause steering to become stuck or insensitive. Although the electric power steering system can provide power assistance, wear and tear of mechanical components may greatly reduce the power assistance effect.
● Steering column failure: The steering column is a key connecting component between the steering wheel and the steering system. If there is a problem with the steering column, such as sticking or damage, it will affect the driver's steering experience and may cause the electric power steering system to misjudge the steering demand.
Environmental factors
The environment in which the vehicle operates may also have an adverse effect on the EPS system. For example:
● Extreme temperature: High or low temperature environments may affect the normal operation of the electric power steering system's motor, sensors, and ECU. High temperatures may cause the motor to overheat, while extremely low temperatures may cause the performance of the motor and electronic components to deteriorate.
● Humid environment: Humid environments may cause electronic components to become damp, which may cause short circuits or electrical failures, affecting the normal operation of the electric power steering system.
Improper maintenance
Although the maintenance requirements of the electric power steering are less than those of the traditional hydraulic power steering system, this does not mean that it does not require maintenance. Long-term lack of maintenance or inspection may cause some hidden problems in the system to be ignored, eventually causing greater failures. Owners should regularly check the operation of the electric power steering, especially when the vehicle is older, to ensure that the electrical connections, sensors and motors are in good condition.
How to detect electric power steering problems?
When there is a problem with the electric power steering, the driver can usually make a preliminary judgment through some obvious symptoms. The following are common manifestations of electric power steering system failures:
● The steering wheel becomes heavier: The driver will feel more effort than usual when turning the steering wheel, especially when turning at low speed. This is a typical manifestation of insufficient EPS power assistance.
● Intermittent failure of steering power assistance: Sometimes the power assistance is normal, and sometimes it fails, especially after the vehicle has been running for a long time. This may be caused by overheating of the motor or instability of the electrical system.
● The instrument panel warning light is on: If there is a problem with the vehicle's electric power steering system, it is usually accompanied by the fault warning light on the instrument panel (usually a light with "EPS" or a steering icon). At this time, the fault code should be checked as soon as possible and repaired.
● Abnormal vehicle noise: If the mechanical parts of the electric power steering system (such as the steering gear) are severely worn, the driver may hear abnormal noise when turning the steering wheel. In this case, the mechanical parts should be checked and repaired as soon as possible.
How to prevent and solve electric power steering problems?
To prevent problems with the electric power steering, car owners can take the following preventive measures:
● Check the battery voltage regularly: Make sure the car's battery and generator are working properly and provide a stable power supply.
● Check the electrical connections: Check the electrical circuits of the electric power steering system regularly to ensure that there are no loose or damaged connections.
● Timely maintenance: Perform regular maintenance according to the time or mileage recommended in the vehicle manual, especially check the status of the electric power steering.
● Avoid extreme driving conditions: Try to avoid long periods of low-speed driving and frequent stop-and-start to reduce the risk of overheating of the motor.
If there is a problem with the electric power steering system, the owner should go to a professional repair shop for inspection and repair as soon as possible to avoid further deterioration of the problem.
