12/12/2019
Modern vehicles rely heavily on sophisticated electronic systems, and one of the most significant advancements in recent years has been the widespread adoption of Electric Power Steering (EPS). Unlike traditional hydraulic systems that use fluid and a pump, EPS systems utilise an electric motor to provide steering assistance, offering improved fuel economy and greater flexibility in vehicle design. However, like any complex component, EPS systems can develop faults. Understanding the common problems, their symptoms, and the best course of action is crucial for maintaining your vehicle's safety and performance.
Understanding Electric Power Steering (EPS)
Electric Power Steering operates without hydraulic fluid, pumps, or hoses. Instead, it uses an electric motor, sensors, and an Electronic Control Unit (ECU) to assist the driver. When you turn the steering wheel, a torque sensor detects the effort applied and sends this information to the ECU. The ECU then calculates the precise amount of assistance needed and directs the electric motor to provide it, making steering effortless at low speeds and firmer at higher speeds for better control. This system is not only more fuel-efficient but also offers finer control and can be integrated with other vehicle systems like stability control.
Common Symptoms of EPS Failure
Identifying EPS problems early can prevent more significant issues and ensure your safety on the road. Here are the most common symptoms drivers experience:
Sudden Loss of Power Steering
This is perhaps the most alarming and immediate symptom. While the steering won't completely fail (you can still steer the car mechanically), it will become incredibly heavy and difficult to turn, especially at low speeds or when parking. This sudden loss usually indicates a complete system failure, often due to a motor or ECU malfunction. It's a significant safety concern and requires immediate attention.
Intermittent Steering Assistance
Instead of a complete failure, you might experience the power steering cutting in and out. The steering might feel normal one moment, then suddenly heavy, then normal again. This erratic behaviour can be frustrating and dangerous, making the vehicle unpredictable to drive. It often points to electrical connection issues, sensor glitches, or a failing ECU struggling to maintain consistent operation.
Unusual Noises from the Steering System
While EPS systems are generally quieter than hydraulic ones, unusual noises are a clear indicator of trouble. You might hear a whining, grinding, or clicking sound when turning the steering wheel. These noises can stem from a failing electric motor, worn bearings within the steering column, or issues with the internal gears of the steering rack where the EPS unit is integrated. Any new, persistent noise should be investigated.
Steering Wheel Vibrations or Notchy Feel
If your steering wheel feels 'notchy' or 'sticky' when turning, or you experience unusual vibrations, it could indicate an EPS problem. This sensation means the assistance isn't smooth and consistent. Possible culprits include issues with the torque sensor providing incorrect feedback to the ECU, internal motor problems, or even mechanical wear within the steering column that the EPS system is trying (and failing) to compensate for.
Dashboard Warning Lights
Modern cars are equipped with sophisticated diagnostic systems. If there's an issue with your EPS, a warning light will illuminate on your dashboard. This is typically a steering wheel icon, sometimes accompanied by an exclamation mark, or a specific "EPS" warning. This light indicates that the system has detected a fault and has often entered a 'fail-safe' mode, potentially reducing or eliminating power assistance. Never ignore these warning lights.
Steering Pulling to One Side
While often associated with wheel alignment issues, a faulty EPS system can also cause the steering to pull consistently to one side. This can happen if a sensor is providing incorrect readings, causing the EPS motor to apply more assistance to one side than the other, leading to an imbalance. If you've ruled out alignment, a deeper EPS diagnostic might be necessary.
Root Causes Behind EPS Problems
Understanding the underlying causes can help in diagnosing and rectifying EPS issues:
Electronic Control Unit (ECU) Malfunctions
The ECU is the brain of the EPS system. It processes sensor data and controls the electric motor. ECU failures can range from software glitches that require reprogramming to internal component failure due to heat, voltage spikes, or age. A faulty ECU can lead to a complete loss of power steering, intermittent issues, or incorrect assistance levels.
Electric Motor Failure
The electric motor provides the actual steering assistance. Overheating, internal winding failures, or worn components within the motor itself can cause it to malfunction or fail entirely. This is a common cause of sudden power steering loss or grinding noises.
Sensor Issues (Torque & Steering Angle)
EPS relies on accurate input from various sensors. The torque sensor, for example, measures how much force you're applying to the steering wheel. If this sensor fails or provides incorrect readings, the ECU won't know how much assistance to provide, leading to heavy or erratic steering. Steering angle sensors also play a crucial role in determining the vehicle's direction and can cause issues if faulty.
Wiring and Connector Degradation
Like any electrical system, the wiring and connectors within the EPS system are susceptible to wear, corrosion, or damage. Loose connections, frayed wires, or moisture ingress can disrupt the flow of power or data signals, leading to intermittent problems or complete system failure.
Battery and Charging System Problems
EPS systems are highly sensitive to voltage fluctuations. A weak car battery, a failing alternator, or poor electrical grounds can lead to insufficient or inconsistent power supply to the EPS unit. This can manifest as intermittent power steering, warning lights, or even a complete shutdown of the system, particularly during start-up or heavy electrical load.
Mechanical Wear and Tear
While EPS reduces the number of mechanical components compared to hydraulic systems, some mechanical elements remain. Bearings, gears, or universal joints within the steering column or rack can still wear out over time, leading to play, stiffness, or noises that might be mistaken for an electronic fault or exacerbated by the EPS system trying to compensate.
The Importance of Professional Diagnostics
Given the complexity of EPS systems, accurate diagnosis is paramount. Attempting DIY fixes without the right knowledge and tools can lead to further damage or, critically, compromise your vehicle's steering safety. Specialist garages use advanced diagnostic equipment to read fault codes, monitor live data, and pinpoint the exact component causing the issue. This precise approach saves time and ensures the correct repair is carried out.
Repairing or Replacing Your EPS Unit: The Smart Choice
Once a fault is diagnosed, you generally have two primary options: replacing the unit with a brand new one or opting for a remanufactured unit. This is where expertise truly matters.
Power Steering Services, established in 1942, are the UK's very first and still a leading brand for automotive Power Steering Repairs. With a growing team of electronic & hydraulic engineers, they boast over 120 years of combined experience with extensive knowledge of evolving power steering and now electric power steering (EPS) systems. They provide an affordable alternative to buying expensive new replacement car parts.
Their aim is to offer the same high standard quality in remanufactured parts as you would expect to get from buying a new unit. The significant advantage of a remanufactured part from a specialist like Power Steering Services is their ability to re-engineer the units to permanently eliminate any design faults. This offers a more reliable solution over a standard replacement. One of the main reasons for this is that a new replacement part will most likely retain the same design fault which caused it to fail in the first place, leading to potential repeat failures. Choosing a remanufactured unit from an experienced provider like Power Steering Services ensures long-term reliability and peace of mind.
Comparison: New vs. Remanufactured EPS Units
| Feature | New EPS Unit | Remanufactured EPS Unit (e.g., from Power Steering Services) |
|---|---|---|
| Cost | Typically higher | Often significantly lower |
| Quality | Original manufacturer quality | Meets or exceeds original quality; often improved |
| Design Faults | Retains original design flaws | Design flaws are identified and permanently re-engineered out |
| Environmental Impact | Higher (new materials, manufacturing) | Lower (recycles existing components) |
| Warranty | Standard manufacturer warranty | Often comprehensive, reflecting confidence in improvements |
| Availability | Generally good, but specific parts can be backordered | Excellent for common failures; specialist stock |
Preventative Measures and What to Look Out For
While EPS systems are largely sealed and maintenance-free, some general vehicle care can indirectly benefit their longevity:
- Maintain your battery: A healthy car battery and charging system ensure the EPS unit receives stable voltage.
- Address warning lights promptly: Never ignore a dashboard warning light. Early intervention can prevent minor issues from becoming major, costly repairs.
- Be aware of changes in steering feel: Any new noises, stiffness, or erratic behaviour in your steering should be investigated by a professional.
Frequently Asked Questions About EPS
Can I drive my car if the EPS warning light is on?
While you can mechanically steer the car, it will be significantly harder and potentially unsafe, especially at low speeds or during emergency manoeuvres. It is strongly advised to have the vehicle inspected immediately by a qualified mechanic. Driving with reduced or no power assistance puts undue strain on the driver and components.
How much does it cost to repair an EPS unit?
The cost varies significantly depending on the specific fault, the vehicle's make and model, and whether you opt for a new or remanufactured part. However, choosing a remanufactured unit from a specialist like Power Steering Services can offer a substantial saving compared to a brand new one, without compromising on quality or reliability.
Is EPS more reliable than traditional hydraulic steering?
Generally, yes. EPS systems have fewer moving parts, no fluid to leak, and are less prone to issues like pump failure or hose bursts. However, they are susceptible to electronic failures (sensors, ECU, motor), which hydraulic systems are not. Both systems have their strengths and weaknesses, but modern EPS is designed for longevity.
What makes Power Steering Services different?
Power Steering Services stands out due to their extensive experience dating back to 1942 and their focus on remanufacturing. They don't just replace faulty parts; their engineers re-engineer units to permanently correct original design flaws, making their remanufactured units often more reliable than a new, off-the-shelf replacement that might still carry the same inherent defect.
Conclusion
Electric Power Steering systems are a vital part of modern vehicle control, offering convenience, efficiency, and precise handling. While they are generally robust, understanding the common problems and their symptoms is key to ensuring your vehicle's continued safety and performance. Prompt and accurate diagnostics by experienced professionals are essential. When faced with an EPS fault, considering a high-quality remanufactured unit from a reputable specialist like Power Steering Services offers a cost-effective, reliable, and often superior solution compared to simply replacing it with a new part that might share the original design flaw. Don't compromise on your steering; address any issues swiftly and wisely.
If you want to read more articles similar to Common Electric Power Steering Problems Explained, you can visit the Automotive category.