obd-raw-data-parser/dist/src/DTC/utils/dtcConverter.js

A lightweight TypeScript library for parsing OBD-II raw data into human readable format. Based on the excellent work of obd-utils by Nishkalkashyap.

const DTC_CATEGORIES = {
    0: 'P',
    1: 'C',
    2: 'B',
    3: 'U'
};
function extractBits(binary, start, length) {
    return binary.substring(start - 1, start - 1 + length);
}
export function hexToDTC(hexValue) {
    // Normalize hex input to 4 characters
    hexValue = hexValue.padStart(4, '0').toUpperCase();
    // Convert to 16-bit binary
    const fullBinary = parseInt(hexValue, 16).toString(2).padStart(16, '0');
    // Extract bits according to the correct positions:
    // First 2 bits: category (00=P, 01=C, 10=B, 11=U)
    // Next 2 bits: first digit
    // Remaining 12 bits: split into three 4-bit groups
    const categoryBits = extractBits(fullBinary, 1, 2);
    const firstDigitBits = extractBits(fullBinary, 3, 2);
    const secondDigitBits = extractBits(fullBinary, 5, 4);
    const thirdDigitBits = extractBits(fullBinary, 9, 4);
    const fourthDigitBits = extractBits(fullBinary, 13, 4);
    // Convert category
    const category = DTC_CATEGORIES[parseInt(categoryBits, 2)];
    // Convert digits
    const firstDigit = parseInt(firstDigitBits, 2).toString(16).toUpperCase();
    const secondDigit = parseInt(secondDigitBits, 2).toString(16).toUpperCase();
    const thirdDigit = parseInt(thirdDigitBits, 2).toString(16).toUpperCase();
    const fourthDigit = parseInt(fourthDigitBits, 2).toString(16).toUpperCase();
    return `${category}${firstDigit}${secondDigit}${thirdDigit}${fourthDigit}`;
}
export function decToDTC(decValue) {
    const hexValue = decValue.toString(16).padStart(4, '0').toUpperCase();
    return hexToDTC(hexValue);
}