Electric power steering (EPS) systems can encounter several issues that affect your vehicle’s handling. Common problems include sensor malfunctions and wiring failures, which often lead to stiffness or loss of assist.
If you notice the EPS warning light activate, or experience difficulty turning the wheel, these could indicate torque sensor issues. Additionally, unusual noises may signal motor or mechanical failures.
Regular diagnostics are crucial to identify faults early and maintain optimal performance. Understanding these issues can help you keep your EPS functioning smoothly, ensuring safety and reliability on the road.
If you are needing power steering repair, bring your vehicle to Springs Brake and Suspension.
What is Electric Power Steering (EPS)?
Electric Power Steering (EPS) is a technology that replaces traditional hydraulic steering systems with electric motors. Unlike hydraulic systems that use power from the engine.
EPS uses an electric motor that is controlled by the Electronic Control Unit (ECU) to provide steering assistance. EPS offers improved fuel efficiency, a more responsive driving feel, and reduced vehicle weight, making it a popular choice for modern cars.
However, while EPS systems are more efficient and compact, they can still encounter issues that may affect the driving experience. Below, we discuss some of the most common EPS problems, their causes, and how to troubleshoot them.
How does the electric power steering system work?
Before discussing the reasons for the failure of the electric power steering system in depth, it is crucial to first understand its working principle.
The electric power steering system monitors the driver’s steering force requirements through sensors on the steering wheel and transmits the signal to the control module.
Which then sends instructions to the electric power motor, and the motor provides additional power to help the driver complete the steering.
Compared with traditional hydraulic systems, EPS does not require mechanical parts such as hydraulic pumps and belts, so it has higher efficiency.
Most Common Electric Power Steering Problems
The reasons for the failure of electric power steering are:
1. Electrical system failure
2. Steering sensor failure
3. Control module (ECU) failure
4. Electric power motor failure
5. Power system problem
6. Mechanical problem
7. Temperature change
8. Moisture intrusion
Although the electric power steering system is relatively stable and efficient, it is not completely problem-free. These 8 points are the main causes of EPS failure, which are described as follows:
#1. Electrical system failure.
The electric power steering system relies on electricity to operate, so any problems related to the electrical system may cause the power system to fail. Common electrical problems include low battery, blown fuses, and short circuits.
- Battery problems: If the car’s battery is low, the electric power motor cannot get enough power supply, which may cause the system to fail. This is especially common in cold weather or when the battery is aging.
- Fuse or relay failure: Some components in the EPS system, such as the motor or control module, rely on the normal supply of power. If the fuse is blown or the relay is damaged, it may cut off the power supply and cause the system to not function properly.
- Wiring problems: Short circuits or poor contact may cause electrical connections inside the EPS system to fail, which may cause steering failure.
#2. Steering sensor failure.
The steering sensor is a core component of the EPS system. It is responsible for detecting the movement of the steering wheel and transmitting information to the control module.
If the sensor fails, the system may not be able to correctly read the driver’s steering needs and provide power to the motor.
- Sensor damage: Due to long-term use or external impact, the steering sensor may be damaged, resulting in inaccurate signals.
- Sensor calibration problems: If the sensor is not calibrated correctly, the power provided by the steering system may not match the actual needs of the driver.
#3. Control Module (ECU) Failure.
The control module is the brain of the EPS system, responsible for analyzing data from sensors and deciding how much power to provide to the power motor. If the control module fails, the power-assisted system will not work properly.
- Software Failure: In some cases, the failure of the control module may be caused by a software problem, especially if the software is not updated correctly when the vehicle upgrades the system.
- Hardware Damage: Since the control module is under a lot of data processing tasks, long-term operation or external impact may also cause damage to the components inside the module.
#4. Power-assisted Motor Failure.
The power-assisted motor is the power source of the EPS system and provides steering assistance for the vehicle. If the power-assisted motor fails, the driver will feel that the steering becomes unusually heavy or completely loses power.
- Motor Overheating: The electric motor may overheat when it is running for a long time, especially in a hot environment or when the vehicle frequently uses the steering function. If the motor overheat protection mechanism fails, it may cause the power-assisted system to suddenly fail.
- Motor Wear: As the vehicle ages, the mechanical components inside the power-assisted motor may wear out, resulting in a decrease in output power or complete failure.
#5. Power system problems.
The normal operation of the EPS system depends on the vehicle’s power system, especially the stable power supply of the generator. If there is a problem with the vehicle’s generator, the EPS system will not be able to obtain a continuous power supply.
- Generator failure: The generator cannot provide enough power to the vehicle, which may cause the EPS system to work abnormally. Generator failure is usually accompanied by abnormalities in other electrical systems, such as dimming of headlights, abnormal instrument panel display, etc.
- Battery aging: Although the battery is mainly used as a backup power supply in the EPS system, if the battery is aged or insufficient, it may also cause unstable power supply to the system, which in turn affects the normal operation of EPS.
#6. Mechanical problems.
Although the electric power steering system mainly relies on electronic components, its final output is still connected to the vehicle’s mechanical steering system. Therefore, mechanical failures may also cause the steering system to fail.
- Steering rack damage: If the steering rack or steering gear is worn or damaged, the electric power system will not be able to provide enough power even if it works normally. At this time, the driver will feel that steering has become extremely difficult.
- Bearing or joint wear: If the bearings or joints in the steering system are worn or rusted, it may also affect the normal operation of the system and cause steering problems.
#7. Temperature changes.
Changes in external temperature may also affect the performance of the electric power steering system, especially in extreme weather conditions.
Low temperatures may cause electrical components to react slowly, resulting in reduced system power, while high temperatures may cause motor overheating or electronic component failures in the control module.
#8. Moisture intrusion.
Although the vehicle’s electric power steering system has protective devices, in extremely humid environments or water ingress, moisture intrusion into the circuit may cause a short circuit or sensor failure.
Especially when driving on wading roads, if the seal is not tight, it may affect the normal operation of electrical components.
Symptoms of Electric Power Steering Failure
Several symptoms can indicate that the EPS system is failing. The most common symptoms include:
- EPS Warning Light
- Loss of Power Assist
- Vehicle Pulling to One Direction
- Whining Noise From Power Steering Motor
- Soft Steering Wheel at High Speed
- Vibrations From Steering Rack
Let us see these symptoms in detail:
#1. EPS Warning Light.
If your electric power steering system fails, it can trigger an EPS warning light on your dash. This light is usually red or yellow, meaning there is a problem with your power steering. If you see this light, you should take your car to a mechanic to have it checked out.
#2. Loss of Power Assist.
If the EPS system fails, you will lose power assist. This means that it will become more difficult to turn the steering wheel.
The loss of power assist can be sudden or gradual. If it is sudden, it can be very dangerous as it can make it difficult to keep the vehicle under control.
If you lose power assist gradually, you may not notice it at first. However, over time, it will become more and more difficult to turn the steering wheel. This can make driving long distances very tiring.
#3. Vehicle Pulling to One Direction.
If your electric power steering system fails, the vehicle may start to pull to one side. This can be very dangerous as it can make it difficult to keep the vehicle in its lane.
The root cause of this problem is typically a malfunctioning sensor or defective power steering motor.
When either of these components fails, they can provide more assistance in turning the vehicle to one side than the other. As a result, the vehicle will begin to pull in that direction.
#4. Whining Noise From Power Steering Motor.
If there are power steering issues, you may hear a whining noise from the power steering motor. This noise is caused by the gears inside the motor grinding against each other. The noise will become louder as the EPS system starts to fail.
In this case, the motor cannot generate the necessary torque to turn the wheels. The electric power steering system may also fail to provide adequate assistance if the motor is not properly sized for the vehicle.
#5. Soft Steering Wheel at High Speed.
If you notice that the steering wheel is softer than usual at high speeds, it could be a sign that the EPS system is failing. The electric power steering offers the ability to adjust the level of assistance based on driving conditions.
For example, more assistance may be provided at lower speeds when it is more difficult to turn the steering wheel, and less assistance may be provided at higher speeds when it is easier to turn the steering wheel.
So, at higher speeds, the steering should become really hard and very soft at slower speeds. However, if the EPS system fails, it may provide unnecessary assistance even at higher speeds. As a result, you may feel the steering wheel slipping.
#6. Vibrations From Steering Rack.
If you notice any vibration in the steering wheel, it is important to have it checked out by a mechanic as soon as possible. The electric power steering system uses a rack and pinion to convert the rotational motion of the steering wheel into linear motion.
This linear motion is used to turn the wheels of the vehicle. If the rack and pinion are not properly aligned, it can cause vibration in the steering wheel.
In addition, if there is excessive play in the rack and pinion, it can also cause vibration. The root cause of this problem is typically a worn-out or damaged rack and pinion.
Common Causes of Electric Power Steering Failure
#1. Bad Connector or Wiring Issue.
Electric power steering systems rely on solid electrical connections to function. A loose, corroded, or damaged connector can cause intermittent or complete power steering failure.
This is more common than many people realize, especially in vehicles exposed to moisture or road salt.
Connectors can develop bent pins, corrosion, or loose terminals that interrupt the signal between the steering module and the motor.
You might notice your power steering works fine sometimes and then suddenly cuts out over bumps or when turning sharply. The problem can be maddeningly intermittent until the connection fails completely.
Check connectors for corrosion, moisture, or physical damage. Sometimes simply cleaning and reseating the connector solves the problem.
#2. Blown Fuse or Relay.
Electric power steering systems draw a large amount of current, so they rely on dedicated high‑amperage fuses and relays. If a fuse blows or a relay fails, the system can lose power instantly, causing complete loss of steering assist with no warning.
This type of failure is usually sudden rather than gradual. You may notice the power steering warning light come on at the same time the steering becomes heavy.
In some cases, the fuse may blow again if there’s an underlying electrical issue, such as a shorted wire or failing motor.
Checking the fuse or relay is one of the simplest diagnostic steps. The fuse box diagram will show which fuse or relay controls the power steering system, and replacement is quick if the component is accessible.
#3. Steering Angle or Torque Sensor Failure.
Electric power steering systems use steering angle and torque sensors to determine how much assist to provide.
These sensors measure how far and how hard you turn the steering wheel and send that information to the control module. If a sensor fails or sends incorrect data, the system may reduce or shut off power steering assist.
A faulty sensor can cause intermittent or sudden loss of power steering. You might notice assist cuts in and out, the steering feels uneven, or a warning light appears on the dashboard.
Because the symptoms overlap with motor and module failures, sensor issues are often misdiagnosed.
Diagnosing a bad sensor usually requires a scan tool capable of reading power steering fault codes and live data. In many vehicles, the sensor is integrated into the steering column assembly, which increases replacement cost.
#4. Electric Power Steering Motor Failure.
Electric power steering systems use a motor mounted either on the steering column or the steering rack.
This motor provides the steering assist. Like any electric motor, it can fail due to wear, overheating, or internal electrical faults. The motor contains brushes, bearings, and windings that deteriorate over time.
When the motor fails, you’ll typically see a warning light on your dashboard along with immediate loss of power steering.
Some systems will store a diagnostic trouble code that helps pinpoint the problem. Unlike hydraulic systems, electric failures are usually sudden rather than gradual.
#5. Faulty Power Steering Control Module.
Electric power steering relies on a control module to manage the motor’s operation. This computer monitors your steering inputs, vehicle speed, and other factors to provide the right amount of assist.
The module can fail due to electrical issues, moisture intrusion, or internal component failure.
A bad control module might cause intermittent power steering operation, complete loss of assist, or erratic steering feel.
The system will usually set a diagnostic code and turn on a warning light. Diagnosing a module problem typically requires a scan tool to read the stored codes.
How to Fix Electric Power Steering Problems?
Step 1: Check the Battery.
Start by inspecting your vehicle’s battery, as a low or dead battery is a common cause of electric power steering problems. Ensure the battery terminals are clean, tight, and free of corrosion.
Use a multimeter to measure the battery voltage; a healthy battery should read around 12.6 volts when the engine is off and between 13.7 and 14.7 volts when the engine is running. If the voltage is too low, recharge the battery or replace it if necessary.
Additionally, check the alternator to ensure it is charging the battery properly, as a failing alternator can also lead to EPS issues. Reassess the EPS system after addressing the battery to see if the problem persists.
Step 2: Use a Diagnostic Scan Tool.
Connect a diagnostic scan tool to your vehicle’s OBD-II port to identify error codes related to the EPS system. These codes can provide detailed information about the issue, such as faults in the EPS motor, steering angle sensor, or wiring.
Follow the scan tool’s instructions to retrieve the error codes and consult your vehicle’s service manual or an online database to interpret their meanings.
Once you pinpoint the issue, take note of any specific components that require further inspection or replacement. Addressing these diagnostic findings one by one will help ensure accurate and efficient troubleshooting of your electric power steering system.
Step 3: Inspect the EPS Motor and Wiring.
If the diagnostic scan tool indicates a problem with the EPS motor or wiring, visually inspect these components for any signs of damage or wear.
Look for corrosion, loose connections, worn-out wires, or any other visible issues that may be causing the system to malfunction. If you notice any damaged wires or connectors, replace them with high-quality replacements.
For EPS motor issues, it’s best to consult a professional mechanic as repairing or replacing this component can be complex and requires specialized tools and knowledge.
Step 4: Check the Steering Angle Sensor.
To check if the steering angle sensor is functioning correctly, turn on your vehicle’s ignition and rotate the steering wheel from lock to lock while observing the EPS system’s behavior.
If you notice any changes in the steering assistance or complete loss of power steering, it may indicate a faulty sensor.
Use a digital multimeter to test the sensor’s output voltage; consult your vehicle’s service manual for specific values. If the sensor fails this test, replace it with a new one.
The steering angle sensor is typically located near the base of the steering column and may require special tools for replacement. If you are not comfortable attempting this on your own, it’s best to seek professional help.
Step 5: Check the EPS Fuse.
Locate the EPS fuse within your vehicle’s fuse box, which is typically found under the hood or beneath the dashboard. Refer to your vehicle’s owner’s manual to identify the exact location of the EPS fuse and verify its amperage rating.
Remove the fuse and inspect it for any signs of damage, such as a broken filament or discoloration, which can indicate a blown fuse.
If the fuse appears to be damaged, replace it with a new fuse of the same amperage rating to avoid further electrical issues.
After replacing the fuse, test the EPS system by starting your vehicle and checking the steering assistance functionality. If the issue persists, proceed to the next troubleshooting step or consult a professional for further diagnosis.
Step 6: Bleed the System.
Although electric power steering systems generally do not require traditional hydraulic fluid, some systems may combine electronic assistance with hydraulic components.
If your vehicle’s EPS system uses hydraulic fluid, it’s important to ensure there are no air bubbles trapped in the system, as this can cause issues with steering performance.
Start by checking the power steering fluid reservoir for proper fluid levels and top it off if necessary, using the fluid type recommended in your vehicle’s manual.
To bleed the system, turn the ignition to the “on” position without starting the engine. Slowly rotate the steering wheel from lock to lock several times to help any trapped air escape.
While doing this, monitor the fluid level and add more if it drops. Be sure to avoid overfilling the reservoir.
Once the process is complete, check the steering function and verify that the fluid level remains stable. If problems persist, it may indicate a more serious issue requiring professional attention.
Step 7: Reset the EPS System.
Resetting your vehicle’s EPS system can also help resolve minor issues and restore normal steering functionality. To reset the system, turn off your vehicle’s engine and wait for a few minutes before restarting it.
While the engine is running, turn the steering wheel from lock to lock multiple times to recalibrate the system’s sensors and control modules. This process can vary depending on your vehicle’s make and model, so consult your owner’s manual for specific instructions.
Following these steps on how to fix electric power steering problems can help troubleshoot and resolve electric power steering problems, but if issues persist, it’s best to seek professional assistance.
A qualified mechanic will have the necessary knowledge and tools to properly diagnose and fix any EPS system issues for optimal driving safety and performance.
How much does it cost to fix electric power steering?
The cost of fixing electric power steering relies on the actual cause of the failure, taxes, labor charge, location, and the dealership or mechanic handling the repair.
If you have a bad power steering control module, the average cost of replacing it should be around $700 and $800. Parts should be around $550-600, while the service fee is around $150-200.
FAQs.
Q: Does Low Power Battery Affect Electric Power Steering?
The majority of cars use hydraulic power steering systems. At the same time, some use electro-hydraulic steering systems.
Only a few cars use electric power steering and, if you own a car with electric power steering, if the battery runs low for any reason, the ECM can turn off the electric power steering.
It can be dangerous If the electric power steering control module switches off the car while in motion. However, if such happens, you can still turn the steering wheel, but it will require more effort.
Q: Can Electric Power Steering Be Adjusted?
Yes, electric power steering can be modified to suit individual preferences since it is electrically controlled. For instance, you can modify the steering weight to high-speed stability and steering feel.
Q: What Does It Mean When The Electric Power Steering Light Comes Up?
The electronic power steering light typically illuminates on the instrument cluster to notify the driver of a problem in the EPS system. Unlike the hydraulic power steering, the EPS does not use steering fluid in providing power steering assist.
If the light comes on, there is no steering fluid level to check; instead, it should be issued with the battery. Try checking your battery connectivity and try a jump-start.
Q: Can cold weather affect electric power steering?
Apparently, summertime is not good for driving. It’s during summer that we leave our homes to commute on icy or snowy cities and towns to get to our workplace.
Drivers face difficulties during this time, and it can be tremendous for drivers who don’t understand the optimal principles and techniques of driving on icy and snowy areas.
Here are two problems you’re likely to face in the summer season when driving with hydraulic, electro-hydraulic, or electric power steering;
Under-Steering: Under-Steering refers to when a driver tries to make a corner and the wheels return to their original direction.
This mainly occurs when driving on high gears or when trying to corner at high speed, but the tires did not grip or make traction on the road. The best way to prevent this from resulting in a collision is to shift to lower gears.
Vehicle pulling to one side after installing winter tires: It can be a fainting experience to see your tires pulling to one side while going to the other side, vice versa.
The cause of these steering issues usually lies in the alignment and not the steering itself. To fix this, take your car to a mechanic to correct the alignment.
Q: Can You Make an Electric Power Steering Light?
If your EPS is too heavy or you want to make it lighter for personal reasons, consult your dealership or mechanic to lighten it to be easier to turn. Power Steering lighting is ideal for you if;
- You use one hand to steer the wheel
- You have reduced strength
- You have rheumatism.
Q: How Do You Check Electric Power Steering Problems?
Electric Power Steering has different working principles from the traditional hydraulic power steering system due to its electronic design.
Instead of having a physical inspection, repairing and replacing faulty mechanical parts, EPS diagnosis involves programming and calibration, and some system work. EPS cannot be diagnosed via physical inspection like the hydraulic steering.
To properly diagnose or service the system, your dealership or mechanic needs to implement the following;
- A scan check for diagnosing system faults that deal with communication and electronic issues.
- Contacting an aftermarket manufacturer for a high-end components rebuild.
- Electronic repair solutions.
Final words
Electric power steering systems offer many benefits, but like any other vehicle component, they can experience issues that require troubleshooting.
By following these steps on how to fix electric power steering problems and conducting regular maintenance on your EPS system, you can ensure its efficient performance and extend its lifespan.
If, at any point during the troubleshooting process, you feel unsure or uncomfortable, it’s best to seek professional assistance from a trained mechanic to avoid causing further damage.
Remember to always prioritize safety when working on your vehicle and take precautions such as disconnecting the battery before conducting any repairs or replacements involving electrical components.
Regularly inspecting and maintaining your electric power steering system will not only save you time and money in the long run but also provide a safe.