Checking the fluid level ATF in the reservoir under the hood - this is the fastest way to determine the type of amplifier, since in systems EGUR there may be no hydraulic circuit at all. If, when you open the hood, you see a tank with a characteristic red or yellow cap, on which an oil can or steering wheel is depicted, you have a classic power steering. The absence of such a reservoir and the presence of a massive electric motor directly on the steering rack or steering column clearly indicates an electric power steering system. Understanding this difference is critical as fault diagnosis methods, maintenance requirements and repair costs for power steering and EGUR are radically different.
Owners often confuse these systems until they encounter the first symptoms: a hum when turning the wheels is characteristic of hydraulics, while a sudden weighting of the steering wheel in a parking lot more often indicates a failure in the electronics or overheating of the electric motor. Electric power steering occupies an intermediate position, combining a pump driven by an electric motor and a hydraulic rack, which requires an integrated approach to testing. Incorrect diagnosis can lead to purchasing the wrong parts, such as belts for a nonexistent pump or sensors that will not physically fit your unit.
Modern cars are increasingly equipped with all-electric systems (EPS), which do not require replacement of fluid and belts, but are sensitive to power surges in the on-board network. At the same time, good old hydraulic systems remain more predictable in extreme conditions, although they require regular monitoring of the tightness of the hoses and the condition of the seals. To accurately identify the unit on your car, you need to visually inspect the engine compartment and pay attention to the presence of pipes leading from the steering rack to the pump.
Visual identification under the hood
Primary diagnosis begins with opening the hood and carefully inspecting the area around the engine and front suspension. For system power steering characterized by the presence of a pump, which is driven by a belt from the engine crankshaft. This unit is usually located on the side of the cylinder block and has a pulley that rotates when the engine is running. High-pressure metal or rubber tubes extend from the pump, which go to the steering rack, located deeper in the engine compartment or under the car.
If in front of you EGUR or an all-electric amplifier, the picture will be different. In the case of electrohydraulics, the pump can be installed separately and run on electricity, without a belt drive, but the fluid reservoir will still be present. Fully electric systems (EPS) are generally devoid of hydraulic components: you will not find any reservoir, no pipes, no pump. Instead, an electric motor with a control unit will be mounted on the steering shaft or on the rack itself.
⚠️ Attention: During a visual inspection, never touch hot engine components or try to unscrew the reservoir cap power steering on a warm car, as the fluid is under pressure and can cause burns.
Particular attention should be paid to the markings on the units. On the pump body hydraulic booster pressure parameters are often knocked out, and on electric motors EGUR You can find a nameplate indicating the voltage and current consumption. The presence of connectors with a large number of wires going directly to the steering mechanism is also a sure sign of the electrical nature of the amplifier. In hydraulic systems, only the level or pressure sensors can be electrical, but not the main drive.
Use a flashlight when inspecting, as power steering tubes are often located in hard-to-reach areas behind the engine or under the intake manifold.
Steering behavior analysis
The nature of the steering operation while driving and when parked gives clear clues about the type of system installed. Power steering starts working immediately after starting the engine, as the pump is driven by a belt. This means that even at idle speed the steering wheel should rotate with minimal effort. However, if the engine stalls, the power steering stops working and the steering wheel becomes “stiff”, although it retains the ability to rotate due to the mechanical connection of the wheels.
In systems EGUR and electric booster The operation of the amplifier depends on the ignition being turned on and the signal from the speed and steering angle sensors. You will often notice that at high speeds the steering wheel becomes heavier artificially (by software) to ensure heading stability, whereas when parking it remains very light. If the steering wheel is heavy when the engine is running, and after rebooting the system it becomes light, this is a clear sign of a malfunction in the electronic control unit or sensors EPS.
- 🚗 A hum or howl when turning the steering wheel to extreme positions is a typical symptom of problems with power steering pump or low fluid level.
- ⚡ Jerking or uneven force when turning the steering wheel often indicates a malfunction of the torque sensor in electric booster.
- 💧 The appearance of oil stains under the front of the car after parking indicates depressurization of hoses or seals hydraulic system.
- 🔋 The lighting of the power steering fault lamp on the dashboard is typical for systems with electric drive and self-diagnosis.
It is also worth paying attention to the dependence of effort on engine speed. In classic power steering When you sharply press the gas in a parking lot, the force on the steering wheel may change briefly due to a jump in pump speed. In electrical systems, the force is stable and does not depend on the operation of the internal combustion engine, since the electric motor is powered from the vehicle’s on-board network. This distinction helps experienced drivers understand which system they are dealing with simply by how it feels when maneuvering.
Technical differences and operating principle
The fundamental difference between the systems lies in the source of energy to create the pressure. B hydraulic booster (power steering) uses the mechanical energy of the engine, transmitted through a belt drive to the pump pulley. The pump creates constant fluid pressure in the system, the excess of which is discharged back into the tank through the bypass valve. This is a simple but energy-intensive circuit that creates a constant load on the motor even when the amplifier is not needed.
Electric booster (EUR/EPS) works on the “on demand” principle. The electric motor turns on only when the driver turns the steering wheel. The torque sensor reads the force on the shaft and the control unit supplies current to the motor, which helps turn the wheels. The absence of constant rotation of the pump saves fuel and reduces wear of parts, since there are no rubbing pairs working constantly. However, such a system is more difficult to diagnose and repair.
There is also an intermediate option - electrohydraulic booster (EGUR). Here the hydraulic pump is driven not by a belt from the engine, but by a separate electric motor. This allows the pump to operate even when the engine is stopped (for example, in the Start-Stop system) and regardless of crankshaft speed. Visually, such a unit is similar to a regular power steering, but it does not have a belt drive, and instead there is an electrical connector to the pump.
| Parameter | Power Steering (Hydraulics) | EUR (Electro) | EGUR (Electrohydraulics) |
|---|---|---|---|
| Energy source | Engine belt | Auto electrical network | Auto electrical network |
| Working fluid | Required (ATF/PSF) | Not required | Required |
| Service | Replacing fluid, belts | Missing | Fluid replacement |
| Dependence on internal combustion engines | High | No | No |
Troubleshooting: power steering vs power steering
Troubleshooting methods vary greatly depending on the type of amplifier. For hydraulic systems Primary diagnosis always begins with checking the level and condition of the fluid. Darkening of the oil, the presence of metal shavings or emulsion (water) in it indicates serious problems with the pump or moisture entering the system. The tension of the drive belt must also be checked; its slippage causes squealing and loss of amplifier efficiency.
In the case of EUR and electric drives diagnostics are shifting to the electrical field. The first step is to scan the system for errors via the OBD-II connector. The amplifier control unit stores fault codes for sensors, motor or power circuits. The mechanical part is checked less often here; attention is usually paid to the integrity of the wiring going to the steering rack and the condition of the contacts, which can oxidize.
⚠️ Warning: If the red steering fault light on the dashboard comes on, operating the vehicle may be dangerous as the power steering may shut off completely at any time.
A common problem power steering is the airing of the system, which manifests itself in the foaming of the liquid and noisy operation of the pump. In electrical systems, an analogue is the overheating of the electric motor when the steering wheel is held in the extreme position for a long time, which leads to the temporary shutdown of the amplifier for protection. Understanding these nuances allows you to quickly localize the problem: if the steering wheel becomes “heavier” after a series of active maneuvers, most likely the thermal fuse is triggered electric motor.
☑️ Power steering diagnostics
Maintenance and resource of components
The service life of components directly depends on operating conditions and timely maintenance. Power steering pump is a wear-out element, as it contains friction pairs (shaft-bearing, blades-stator). The average resource of a high-quality pump is 100-150 thousand kilometers, but if low-quality fluid is used or it is not replaced in a timely manner, it can be halved.
Electric motors EUR can last the entire service life of the car, since they do not have rubbing pairs in the traditional sense. However, they are vulnerable to vibrations and moisture. The control unit, often built into the motor housing, can fail due to voltage surges or poor contact in the connector. The mechanical part of the steering rack (gears, shafts) wears out equally in both cases, but in hydraulic systems the oil partially performs a lubricating function, prolonging the life of the unit.
Ownership costs also vary. Hydraulic systems require regular costs for the purchase of fluid, belts and, eventualmente, replacement of the pump or high-pressure hoses. Electrical systems require little to no routine maintenance, but if they break down, the cost of repair can be higher due to the high cost of electronic components and the need for complex calibration after repair.
Secrets to extending power steering life
Do not hold the steering wheel in the extreme position for more than 5 seconds - this causes a sharp increase in pressure and temperature of the fluid, which leads to rapid wear of the seals and pump. If you have to stand with your wheels turned out, release the steering wheel a little to relieve pressure.
Comparison table of characteristics
For a final understanding of the difference between the systems, it is convenient to summarize all the data in a single table. This will help you quickly navigate when choosing a car or when planning repairs. Pay attention to the “Comfort” column, since many drivers subjectively evaluate this particular parameter without going into technical details.
| Characteristics | Classic power steering | Electric power steering (EUR) | Electrohydraulics (EGUR) |
|---|---|---|---|
| Steering sensitivity | Constant, depends on speed | Adaptive, speed dependent | Close to power steering, but more stable |
| Fuel consumption | Higher (power take-off) | Below (works as needed) | Below (no connection with internal combustion engine) |
| Noisiness | May make a noise when worn | Silent operation | Quiet pump operation |
| Environmental friendliness | Risk of oil leakage | No liquids | Risk of oil leakage |
Final recommendations for selection and operation
Understanding which system is installed on your car - power steering or EUR — allows you to correctly build a service strategy. If you have hydraulics, make it a rule to check the condition of the fluid and visually inspect the hoses once a year. For owners of electrical systems, the main advice would be to be careful with electrics: avoid washing the engine with high pressure in the area of the steering rack and monitor the condition of the battery.
When purchasing a used car, availability electric booster is often a plus, indicating a more modern design, but requires careful inspection of the electronics. Power steering being more archaic, it often turns out to be more reliable in conditions of bad roads and lack of quality service, due to its maintainability and simplicity. In any case, timely identification of signs of malfunction will save you money and keep you safe on the road.
The main conclusion: the power steering requires regular replacement of fluid and belts, but is repairable. The ESD does not require maintenance, but is expensive to repair if the electronics fail.
Is it possible to add power steering fluid to the EUR?
No, in systems EUR (electric boosters) and EPS liquid is not structurally provided. An attempt to pour oil into it will lead to damage to the electronic components and failure of the unit. The liquid is used only in power steering and EGUR.
Why does the pump howl after changing the fluid?
Howling after replacement often indicates airing of the system power steering. It is necessary to smoothly turn the steering wheel several times from lock to lock with the engine running (without holding it in extreme positions) to expel the air. It could also be due to poor quality fluid or a type that does not meet the manufacturer’s specifications.
What is better for the city: power steering or electric power steering?
Definitely preferable for the city EUR or EGUR. They provide easier handling at low speeds when parking and do not waste fuel running the pump in traffic jams. In addition, the absence of a belt drive reduces noise and vibration, which is important in dense city traffic.
How often should the power steering fluid be changed?
Manufacturers often claim that the liquid is filled for the entire service life, but practice shows that to extend life pump and its slats should be changed every 60-80 thousand kilometers or once every 3-4 years. Darkening of the liquid and the appearance of a burning smell are signals for immediate replacement.