When graphed with each other, they intersect at specific intervals, which allows the EPS module to rationalize voltage inputs and set various trouble codes.
Genisys scan tool dtc 21 code#
A C1521 code would set if a motor malfunction (loss of steering assist) occurs (see scan tool screen capture 3.) The voltages produced by the torque and steering position sensors are positive and negative values that mirror each other and are similar in function to those produced by an electronic throttle. To illustrate, a 2014 Toyota Camry would set a C1511 code if the steering position sensor doesn’t produce a rational input voltage. A “U-series” code indicates a data-sharing problem between the EPS, ECM, ABS and other system modules. For example, a “C-series” code indicates problems within the feedback and electromechanical assist portions of the system. The electromechanical assist is usually a directionally controlled, pulse-modulated electric motor that is geared into the steering shaft.ĭiagnostics on any EPS system should begin by scanning the EPS module for diagnostic trouble codes. The vehicle speed input modulates steering sensitivity in relation to vehicle speed. Scan tool screen capture 3 – The torque sensor signal inputs are displayed as positive and negative voltages, as are the steering position sensor input voltages.Īs mentioned at the outset, the primary EPS data inputs include voltage signals from the torque sensor and steering position sensor and a vehicle speed input - generally from the ECM - to the power steering module. The beauty of electric steering is that all of the steering feedback functions are incorporated into the power steering module, which allows the system to be fine-tuned by reprogramming the module’s software. As mentioned above, the torque and steering position sensors might also provide inputs to other systems, including the vehicle stability control system. Although configurations might vary, the basic electric steering system consists of the power steering control module, assist motor, torque sensor and steering position sensor. In other configurations, the EPS module, steering torque and steering position sensors can be individually replaced. Since many electric steering systems aren’t field serviceable, they are usually replaced as a unit. The steering gear is then aligned to the thrust centerline by adjusting individual toe angles on the front wheels. To steer correctly, all four wheels must be aligned in relationship to the thrust centerline of the vehicle. Manual rack-and-pinion systems provide steering feedback by machining their pinion and rack gears in the same manner. The steering rack concept results in a more precise steering system that doesn’t contain as many moving parts. The rack-and-pinion steering gear, or steering rack as it’s more popularly known, replaced the more complex “parallelogram” steering system of steering gear, pitman arm, idler arm and drag link. The rack-and-pinion steering gear is a more current steering system that was popularly introduced during the late 1960s. The sector gear not only converts the rotary motion of the steering wheel into a side-to-side motion that steers the vehicle, it also multiplies the torque created by the steering wheel. The steering shaft is connected to a worm gear that bears against a sector gear in the steering box. The concept is relatively simple: Torque created at the steering wheel is transmitted to the steering gear via the steering shaft.
Genisys scan tool dtc 21 manual#
To better understand how a steering gear might affect steering feedback, let’s examine how a manual steering gear achieves that goal in many early imports. Scan tool screen capture 2 – This scan tool screen displays the steering position 2 voltage, the steering wheel position in degrees of rotation and the EPS motor command amperage.