Power steering makes turning the wheel easy at low speeds and during parking. When it starts to fail, you will notice heavier steering, whining noises from the pump, or fluid leaks under the vehicle. This guide covers the most common power steering problems across both hydraulic and electric systems and how to diagnose them.
Hydraulic Power Steering
Most older and many current vehicles use a hydraulic power steering system consisting of a belt-driven pump, a fluid reservoir, high-pressure hoses, and a steering rack or gearbox with an integrated hydraulic actuator. The pump pressurises power steering fluid and routes it to the rack, where it assists your steering input.
Common Hydraulic Issues
A whining or groaning noise that gets louder when turning the wheel is the most common symptom. Low fluid level is the first thing to check – look at the reservoir (usually near the front of the engine bay) and top up if low with the correct fluid type specified in your workshop manual. If the level drops repeatedly, there is a leak. Common leak points include the high-pressure hose connections (look for wet/oily fittings), the rack seals (visible as fluid dripping from the steering rack boots), and the pump shaft seal.
A pump that whines even with correct fluid level may have air in the system (usually after a fluid change or hose replacement – bleed by turning the wheel lock to lock several times with the engine running), worn internal components, or a failing bearing. Heavy steering only at low speed with no noise may indicate a failing rack or a restriction in the fluid lines.
Electric Power Steering (EPS)
Most modern vehicles use electric power steering, which replaces the hydraulic pump with an electric motor mounted on the steering column or rack. EPS has no fluid to leak and no belt to wear, but it can still fail. Common EPS faults include a failing torque sensor (the sensor that measures how much force you are applying to the wheel), a faulty EPS motor, or a wiring/connector fault. EPS problems typically trigger a power steering warning light on the dashboard and store a diagnostic trouble code that can be read with an OBD-II scanner. Your workshop manual includes the EPS diagnostic flowchart and sensor specifications.
Power Steering Fluid
On hydraulic systems, using the correct fluid is important. Some vehicles use dedicated power steering fluid, while others specify ATF (automatic transmission fluid). Some European vehicles require a specific synthetic fluid. Using the wrong type can damage seals and cause premature pump wear. Your workshop manual lists the exact specification.
When to Get It Checked
Any sudden loss of power steering assist while driving is a safety concern, as the steering becomes much heavier. Pull over safely and investigate. On hydraulic systems, a snapped serpentine belt will cause immediate loss of assist along with loss of charging and possibly cooling. On EPS systems, a sudden loss of assist followed by the warning light usually indicates an electrical fault that needs professional diagnosis.
Your workshop manual provides the diagnostic procedures, fluid specifications, belt routing, and component testing values for your vehicle’s steering system. MechanicMate offers PDF workshop manuals for over 960 models at mechanicmate.net/shop.
