Electric power steering repair: a modern approach

Modern cars have a variety of electronic systems that ensure comfort and safety while driving. One of the key systems responsible for vehicle handling is the Electric Power Steering (EPS). This component makes driving the car much easier, especially at low speeds and when manoeuvring. Failure of the EPS carries a serious risk, so do not hesitate to visit a car service centre. In most cases, electric power steering malfunctions can be reliably repaired so that it will serve for a long time.

The use of modern diagnostic methods allows us to effectively detect even the most minor power steering problems and promptly fix them, ensuring smooth operation of the car and safety on the road.

EPS repair is performed in several stages:
      •  Diagnosis and identification of the cause of the malfunction;
      • Replacement of defective components or elimination of a software error;
      • Post-repair testing and inspection;
      • Adaptation of the unit on the vehicle.

Diagnosis and identification of the cause of EPS malfunction

One of the first steps in diagnosing an EPS is to connect diagnostic tools (scanners) to the vehicle. Modern cars are equipped with a large number of sensors and internal diagnostic systems. With an automotive diagnostic scanner, you can access error codes and control system data to help identify potential problems.

To maximise the accuracy of power steering diagnostics, it should be diagnosed with the vehicle's electrical system disconnected from the vehicle's electrical system to ensure that the diagnostic result is not affected by possible faults in the vehicle's control system.

The best tool for power steering diagnostics – is the MS561 PRO tester, which can run on «table» more than 4,000 bus-controlled EPS and ECU units: CAN, CAN-FD and FlexRay, as well as those controlled by PWM signals and various special signals. The MS561 PRO tester checks both the electrical components and the mechanical part of the ESC unit. During diagnostics MS561 PRO provides a lot of useful information that makes it easier to find the cause of the malfunction:
      • universal cable connection diagram to the unit;
      • the normal (correct) current consumption that the unit under test should have;
      • the data packets received from the unit and their decoding;
      • list of non-critical errors that may occur when the EPS is operating outside the on-board network of the car. 

To quickly and easily find EPS faults with the MS561 PRO tester, you can take the online course «Diagnosis and repair of EPS units» at the MSG Equipment training centre. This course reveals the methodology of diagnostics of electric power steering unit faults and how to solve all the problems.

Electric Power Steering Repair

After identifying the fault, the faulty components need to be replaced. This may be the electric motor, steering position sensor, electronic control unit or other elements of the booster. The repair process is different for each unit. Special tools may be required to disassemble the power steering unit. MSG Equipment has a large number of specialised wrenches and jigs available to ensure that the integrity of the EPS parts is maintained during disassembly of the unit.

After replacing certain components, such as sensors, in order for the ESC system to correctly detect steering wheel position and respond to control signals, they must be calibrated. This is an important step to ensure that the EPS works properly and meets the manufacturer's specifications. The procedure can also be performed with the MS561 PRO tester.

Test and check power steering after repair

After the repair is complete, the power steering should be tested and verified. Careful testing helps ensure the quality of the repair and ensures driver safety.

Adaptation, programming and linkage of the repaired steering rack

Different components such as the electric motor, steering position sensor or electronic control unit may have been replaced or reconfigured during the repair. This may affect the repaired power steering installed on the vehicle in such a way that the repaired power steering does not work properly. For this purpose, one of the following actions is carried out: adaptation, programming or binding. This is individual and depends on the vehicle and the power steering unit.

The final point in the restoration of the power steering rack – is to do a camber to ensure optimum steering and driver comfort.