How to Diagnose EPS Faults Using the MS561 PRO Tester

The Electric Power Steering (EPS) system is an integral part of most modern vehicles. It ensures precise, reliable, and smooth steering operation while also integrating with safety systems, autopilot, and automatic parking. However, like any complex electronic system, EPS is prone to malfunctions that can affect driving safety.

In modern vehicle repair, diagnostic equipment plays a key role, allowing for quick and accurate identification of the source of the fault. One such example is the MS561 PRO tester, specifically designed for testing and repairing electric power steering systems.

EPS Faults and How the MS561 PRO Diagnoses Them

1. Malfunctions in torque or steering angle sensors:

• Uneven steering behavior;
• Assist is present only in one direction;
• Wheels may turn on their own when the engine starts.

How the MS561 PRO helps:

• Reads diagnostic trouble codes (DTCs) indicating sensor failure;
• Allows testing of a removed steering rack by connecting it to the tester. Using Live Data, you can analyze real-time parameters, including response to steering input and sensor output signals.

2. Wiring and connection issues resulting in the assist unit switching off or operating intermittently.

Role of the MS561 PRO in diagnostics:

• Rules out faults in the unit itself by performing standalone testing on a bench or in the vehicle with the EPS completely disconnected from the vehicle’s electrical system;
• Determines whether the unit operates outside the vehicle by supplying power and signals via CAN/FlexRay buses.

3. EPS control unit software malfunction, which may manifest as sudden EPS shutdown with no apparent fault cause.

What the MS561 PRO does in this case:

• Reads software and firmware version information from the EPS control unit;
• Allows direct firmware flashing from the tester’s software—without the need to search for firmware files or use additional tools;
• Supports VIN and parameter data upload/replacement to ensure the unit works correctly with a specific vehicle.

4. EPS control unit failure after an impact or water ingress, usually accompanied by:

• No EPS response to steering input;
• CAN communication errors or complete “silence” from the EPS.

How to check with the MS561 PRO:

• Connect to the EPS control unit;
• Verify communication, read DTCs, check the current consumption level, and compare it with reference values provided in the software.

5. Mechanical EPS damage:

• Grinding, crunching, or knocking noises while steering;
• Steering play or binding.

How the MS561 PRO helps:

• Although the mechanical part of the rack is inspected visually, the MS561 PRO ensures the electronics are functioning properly;
• After repairs, the unit can be tested immediately to confirm the repair’s success.

Why Choose the MS561 PRO for EPS Diagnostics

1. Wide vehicle coverage.

Works with most vehicles, including new models using CAN-FD and FlexRay buses as well as non-standard communication protocols.

2. Flexible connection system.

Comes with a universal cable compatible with most units, with connection diagrams available in the tester’s software. A universal FlexRay cable and numerous dedicated cables are also available. All cables are high quality and the right length.

3. Built-in power supply.

Enables testing of the unit under load for greater diagnostic accuracy.

4. Live Data and advanced diagnostic functions:

• View EPS parameters in real time;
• Read module information: VIN, software versions, hardware data, etc.;
• Display DTCs with classification into critical and non-critical;
• Check CAN communication integrity;
• Compare current consumption with reference values—an important factor in diagnosing control unit issues;
• Full support for Tesla steering racks, including DTC/Alert reading and Live Data.

5. Special functions:

• Removal of “non-erasable” errors;
• VIN and parameter changes to adapt the module to another vehicle;
• Firmware and configuration files are built into the program—no need to search for them manually.

6. Standalone operation.

The software does not require a constant internet connection—everything needed is stored locally in the device’s memory. Internet is only required for updates.

7. Support and community.

MS561 PRO buyers gain access to technical support and a Telegram community where they can exchange experiences, receive advice, and get repair instructions.

Conclusion

Finding the cause of electric power steering malfunctions can be quick and accurate when using the right equipment. The MS561 PRO is a convenient and versatile tool that helps technicians test various types and brands of EPS units, including modern models used in hybrid and electric vehicles. It also enables software operations on the unit and confirms its proper functioning after repairs.