1. Design features of EPS systems in vehicles of Asian manufacturers.
2. Faults of steering rack MA107 in Mazda 6 2010-2013.
3. Controller MS561 and adapter MS550: devices for diagnostics and repair of steering racks.
It’s hard to imagine a modern vehicle that would not be equipped with electric steering. Ease of steering is one of the most essential and want-satisfying qualities of a car. Due to their apparent advantages, electric power steering systems are installed in the majority of the latest vehicle models.
There are several widely-used designs, where the EPS unit is integrated into a steering rack. The EPS systems installed in Asian vehicles (Lexus, Mazda, Hyundai, Honda, Toyota, and others) have their unique design: an electric power steering unit of such a rack is installed separately from it and is connected to it through the vehicle wiring.
Compared to a steering rack where the electronic control unit is installed directly on it, this solution creates more favorable conditions for the ECU operation: fewer temperature differences and vibration, reduced the physical and chemical impact of the road surface. However, in case of failure, steering racks of this type are difficult to diagnose without special equipment.
Diagnostics and repair of EPS racks of Japanese manufacture
Drawing on Master Service specialists’ years of experience, we can say that in 96% of cases, a steering rack must be dismounted from the vehicle for its further diagnostics and repair. There are very few cases when the problem can be solved with the help of a special diagnostic scanner.
To detect a fault, special signals must be broadcasted to the electronic components of a steering rack. In the chain of Master Service workshops, we use controller MS561 and adapter MS550 to solve the problem. Both devices are connected to a steering rack via special cables, thus simulating the connection of the unit to a vehicle.
For example, let’s consider in detail the fault that most often happens in steering racks MA107 used in Mazda 6 YOM 2010-2013:
- the effort applied to turn the wheel left is different from the one applied to turn it right;
- when we start the engine, the wheel turns to one of the two sides to its end position.
In the majority of cases, these symptoms signal the torque sensor trouble. When we connect the steering rack to both controller MS561 and adapter MS550, we can see that the torque sensor readings are equal to zero in a static position. In this case, the EPS electronic control unit receives a false signal, which causes the above-described effect.
To eliminate the fault, we must dismount the torques sensor, disassemble it, and assess the condition of a guide bushing. If the bushing has signs of wear only, the torque sensor can be assembled and mounted back to the steering rack. After that, the rack must be calibrated. In case of mechanical damage, the sensor must be replaced.
The new sensor must be calibrated. For this purpose, we can use controller MS561 and adapter MS550.
Therefore, MS561 is an essential tool for diagnostics and repair of steering racks. In addition to it, controller MS561 can be used for diagnostics and repair of HPS racks and pumps operating under protocol FlexRay. The equipment connection is made via special cables.
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