Design and development of a portable diagnostic tester for fault detection in EFI vehicle control systems

The evolution of automotive technology has significantly advanced with the adoption of Electronic Fuel Injection (EFI) systems, which offer superior fuel efficiency, environmental friendliness, and enhanced vehicle performance compared to traditional carburetor systems. However, the complexity of EFI systems necessitates sophisticated diagnostic tools, often inaccessible to small-scale workshops due to high costs and proprietary limitations. This study presents the design and development of a Portable Diagnostic Tester as an affordable and effective alternative for diagnosing faults in EFI control systems, compatible with both OBD I and OBD II systems. The Portable Diagnostic Tester was constructed using an ATMega 8 microcontroller, a 16x2 LCD display, photodiode sensors, and supporting circuitry. It decodes engine trouble codes via onboard diagnostics, displaying fault information with improved accuracy over manual methods. Testing was conducted on various EFI vehicles, demonstrating the Portable Diagnostic Tester's reliability in identifying issues such as sensor malfunctions. Notably, the device performed optimally under low-light conditions, with daytime performance affected by ambient light interference. The Portable Diagnostic Tester 's simplicity, cost-effectiveness, and accessibility provide a viable solution for small workshops, enabling efficient diagnosis of EFI issues without reliance on high-cost scan tools. Future enhancements could include extended compatibility, user-friendly interfaces, and additional functionalities to rival commercial diagnostic tools.