Abstract: The present invention features a diagnostic method for assessing intermittent failures which occur in the components and systems of material handling vehicles. The material handling vehicle of this invention uses an on-board microprocessor and display to allow an operator to determine whether any intermittency is present in the internal systems. The microprocessor is programmed to analyze each system during normal vehicular operation. The program is divided into two vehicular modes, "normal operating" and "program". During the normal operating mode, the vehicle operator is warned of a problem by different audible tones and patterns. A fault code scrolls across the vehicle display screen, indicating the nature of the failure. The program mode can then be entered to assess just where the problem is located. The program mode is divided into three additional modes: "maintenance mode", "configure mode" and "learn mode".

Abstract: The present invention features a system and method for preventing overheating of a motor and/or power amplifier of a material handling vehicle by controlling the performance of the vehicle as a function of motor and/or power amplifier temperature. Temperature sensors are connected to the motor and power amplifier for determining their operating temperatures. A controller is connected to each temperature sensor and to the motor for controlling acceleration of the motor as a function of either or both temperatures, so that both the motor and the power amplifier will not overheat. In controlling acceleration of the motor, the invention provides a mechanism for changing acceleration by discrete steps or continuously according to a performance curve which may be linear or otherwise.

Abstract: The present invention features a material handling vehicle identification system. The material handling vehicle has a universal system processor for controlling the vehicle speed, acceleration, direction and motion of a plurality of different vehicles. A semiconductor memory device is permanently affixed to the chassis of the vehicle during the manufacturing process. This memory device contains a unique identification tag. The identification tag is remotely disposed from, but operatively connected to the system processor. The identification tag includes data for uniquely identifying the material handling vehicle. The system processor can control the performance of the vehicle as a function of the data in the identification tag, whereby the system processor becomes customized to operate consistant only with the vehicle in which it is installed.