What does it mean when it says power steering assist fault?
A power steering assist fault is a warning that your vehicle’s steering assist system has detected a problem. In many cases you’ll notice heavier steering or a loss of steering assistance, and you should have the system checked promptly to prevent a safety risk.
Understanding power steering assist and the fault message
Electric vs hydraulic systems
Most new vehicles rely on electric power steering (EPS), which uses an electric motor and sensors to provide steering assistance. Older or some heavy-duty systems use hydraulic power steering (HPS), driven by a belt-connected pump and hydraulic fluid. The message “Power Steering Assist Fault” can appear when either system detects an abnormal condition in its sensors, motor, fluid (for hydraulic), or control circuitry.
Commonly, the fault means the EPS control module, torque/position sensors, wiring, or the motor has reported an error, or the hydraulic system is not receiving proper pressure or fluid. Software glitches can also trigger the warning even when hardware is functioning correctly.
- Faulty electric steering motor or torque sensor
- Low or contaminated hydraulic fluid, or a failing pump
- Low battery voltage or alternator problems affecting EPS power
- Worn steering rack, bail/recirculating components, or belt slippage in hydraulic systems
- Outdated or corrupted EPS/ECU software
In practice, the fault can stem from a single component or a combination of electrical and mechanical issues. Diagnosis typically requires a manual inspection and reading stored fault codes with an OBD-II scanner, sometimes supplemented by manufacturer-specific diagnostics.
What the fault means for driving and safety
When the system detects a fault, the vehicle may reduce or disable steering assist to protect the steering components and avoid unpredictable behavior. This can lead to noticeably heavier steering, especially at parking speeds, and slightly altered steering feel at higher speeds. Some vehicles will enter a safe or limp mode with limited assist to help you reach a service location.
- Heavier steering effort, particularly at low speeds or while maneuvering
- Potentially reduced response or delayed steering input
- Possible transition to reduced assist or no assist to preserve safety
- Warning lights or messages on the dash indicating a steering fault
Because the exact behavior depends on the vehicle model and whether the system is EPS or hydraulic, drivers should treat the warning as serious but not always immediately dangerous. Do not ignore it, especially if you notice unusual steering feel, odd noises, or warning indicators.
What to do if you see the fault
Acting quickly can reduce risk and prevent further damage. The following steps balance safety with practical next steps:
- Find a safe place to pull over and assess the situation. If steering feels completely unresponsive or dangerous to drive, call for roadside assistance.
- If you have hydraulic power steering, check the fluid level and look for leaks. Do not drive long distances with a low fluid condition.
- Check the 12-volt battery and alternator health; EPS often relies on stable electrical power.
- Have an OBD-II scan performed to pull fault codes from the steering system and related modules. Note codes to share with a technician.
- Inspect fuses and basic wiring connections to the steering module and pump/motor if you can safely access them.
- Schedule professional service promptly. A persistent steering fault can compromise safety, especially in emergencies or high-speed driving.
Conclusion: The warning signals a systemic issue in the steering assist system. While some cars may still be drivable with reduced assist, you should seek diagnostic and repair service as soon as possible.
What to expect during repair
Repairs depend on the underlying cause and may involve one or more of the following:
- Replacement of EPS motor, torque sensor, or related steering electronics
- Repair or replacement of wiring harnesses, connectors, or fuses
- Hydraulic system service: pump, hoses, or fluid replacement; possible rack or steering gear work
- Software update or re-flash of the EPS control module or vehicle software
- Battery or alternator replacement if power supply contributed to the fault
Repair costs and timelines vary by model and fault severity. A professional mechanic or dealership can provide a targeted diagnosis and estimate after retrieving the fault codes and inspecting the system.
Summary
A “Power Steering Assist Fault” indicates the vehicle’s steering assist system has detected a problem affecting electric or hydraulic support. Causes range from sensor or motor faults and wiring issues to fluid problems and software glitches. The immediate effect is typically heavier steering and potential loss of assist, which can impact maneuvering safety. If you encounter this warning, pull over safely, check basic conditions, scan for codes, and seek professional diagnosis and repair promptly to restore reliable steering performance.
