What is the most common cause of power steering failure?
The most frequent cause of power steering failure is a leak in the hydraulic system that leads to a low power steering fluid level, which removes the hydraulic assist. In newer cars with electric power steering (EPS), electrical faults can cause issues, but hydraulic leaks remain the dominant problem for the majority of vehicles still using hydraulic assistance.
Understanding the two main power steering setups
Most vehicles fall into one of two categories: traditional hydraulic power steering (HPS) which uses fluid and a pump driven by the engine, and electric power steering (EPS) which uses an electric motor and sensors to provide assist. Each setup has its own common failure modes, though leaks and low fluid levels are the classic culprits in hydraulic systems, while sensors and motor faults dominate in EPS.
Hydraulic Power Steering: Common Failure Modes
Before listing the typical hydraulic causes, it’s helpful to know what to inspect in the system that most often loses its hydraulic assist.
- Fluid leaks from hoses, seals, rack-and-pinion connections, or the pump itself
- Low power steering fluid level due to leaks or improper initial fill
- Worn or failing power steering pump, reducing pressure and assist
- A slipping or damaged drive belt that drives the power steering pump
- Contaminated or degraded power steering fluid that reduces lubrication and flow
Leaks and worn components are the most common pathways to reduced or completely lost steering assist in hydraulic systems. When leaks occur, you may notice puddles under the car, darkened fluid on nearby components, or a whiny pump noise as you turn the wheel.
Diagnosis and maintenance tips for hydraulic systems
To prevent or address hydraulic failures, consider these practical steps and checks. Regular maintenance and prompt repairs can restore smooth steering and prevent sudden loss of assist.
Electric Power Steering: Common Failure Modes
Electric power steering relies on a motor, sensors, and a controller. Issues here tend to be electrical or software-related rather than fluid-related, though some hybrid or mixed systems may still show hydraulic symptoms.
- Faulty steering angle or torque sensor that misreads steering input
- EPS motor or control unit failure, causing loss of assist or erratic steering
- Damaged wiring, connectors, or communication faults (CAN bus) between components
- Electrical supply problems, such as low battery voltage or alternator issues
- Software or firmware glitches that affect calibration and response
EPS failures are often signaled by warning lights on the dashboard and may feel like stiffness, abrupt changes in assist, or total loss of steering assist, especially at certain speeds or temperatures.
Diagnosis and maintenance tips for EPS
When facing EPS issues, a professional diagnostic is usually required to read fault codes and test sensor readings, motor performance, and the electrical system. Prompt attention is important to prevent unsafe steering conditions.
What drivers should watch for and do
Recognize the symptoms early and act safely. If you notice stiff steering, unusual noises, or a warning light related to power steering, schedule a diagnostic check as soon as possible. Do not drive long distances with a suspected steering issue.
Maintenance and prevention
Regular upkeep can prevent the most common power steering failures, whether hydraulic or electric. Consider the following preventive measures.
- Check power steering fluid level regularly ( hydraulic systems ) and inspect for leaks
- Inspect the drive belt for wear and replace as needed
- Use the fluid type specified by the manufacturer and avoid mixing products
- Have the system flushed or serviced at recommended service intervals
- For EPS, ensure the vehicle’s battery and charging system are healthy to avoid voltage drops
Preventive maintenance helps keep steering responsive and reduces the risk of unexpected failures on the road.
Summary
In summary, the single most common cause of power steering failure in hydraulic systems is a leak that leads to a low fluid level, diminishing or removing hydraulic assist. In electric power steering systems, the problem more often lies with sensors, motors, or controller electronics. Regular fluid checks, belt inspections, and proper maintenance—plus timely diagnostics when warning lights appear—are the best defenses against sudden steering problems.
What is the average cost to fix power steering?
The cost to fix power steering can vary from less than $100$ 100$100 for a simple fluid top-off to over $1,000$ 1 comma 000$1,000 for a full rack replacement, with a power steering pump replacement averaging $500 to $900. The final price depends on the specific part that needs repair or replacement, the make and model of your vehicle, the cost of parts (new, used, OEM, or aftermarket), and labor rates.
This video explains the cost of replacing a power steering pump: 59sLearnToDIY360YouTube · Jan 24, 2025
Common power steering repairs and their costs
- Power steering fluid replacement or flush: \$10 to \$20 for a simple top-off, or \$172 to \$204 for a complete flush.
- Power steering pump replacement: \$500 to \$900 on average, depending on parts and labor.
- Power steering hose replacement: \$150 to \$300.
- Power steering rack replacement: \$500 to over $1,200$ 1 comma 200$1,200, which is a more extensive and costly repair.
- Power steering leak repair (e.g., hose or line): \$60 to \$220.
- Pressure valve replacement: Around $10$ 10$10.
Factors that influence the cost
- Vehicle make and model: Luxury or large vehicles often have more expensive parts.
- Parts used: New, remanufactured, or used parts will have different costs. OEM parts are often more expensive than aftermarket ones.
- Labor: Hourly labor rates vary by location and shop, and can significantly increase the final price.
- Extent of the damage: A leaky hose is a much cheaper fix than a complete rack and pinion replacement.
How to save money
- DIY: If you are comfortable with car repairs, doing some tasks yourself can save on labor costs.
- Shop around: Get quotes from several different mechanics to compare labor rates and part prices.
- Consider used parts: A used pump can be cheaper, but it may not last as long as a new one.
- Preventative maintenance: Regularly checking your power steering fluid level during scheduled maintenance can help prevent minor issues from becoming major, expensive repairs.
This video explains how to check for power steering pump failure: 27scar PROblemsYouTube · May 5, 2023
Why do I have to keep refilling my power steering fluid?
Repeatedly refilling power steering fluid often indicates a leak in the system, commonly from hoses, seals, or the power steering pump. Inspect the reservoir, high-pressure lines, and rack-and-pinion seals for wetness or damage. Check for fluid pooling under the vehicle.
How do you know if your power steering module is bad?
If you are having a hard time turning the steering wheel, something is likely wrong with the power steering system. Low power steering fluid in the reservoir might diminish the power assist and is a sign of a leak. A faulty power steering pump or a worn (or broken) serpentine belt could also be the culprit.
What is the most common power steering problem?
5 Common Power Steering Problems
- Leaking Power Steering Fluid — The power steering system uses a special fluid to transfer the pressure to change the direction of your wheels.
- Cracked, Peeling or Worn out Hose — Every part of your vehicle wears out with time.
