@emdzej/j2534-driver

The J2534Device class — full SAE J2534 PassThru API implementation for the Tactrix OpenPort 2.0. Supports CAN (11/29-bit), ISO 15765 (ISO-TP / UDS), ISO 9141 (K-line slow init), and ISO 14230 (KWP2000 fast init).

Transport-agnostic: pair with one of the @emdzej/j2534-*-transport packages depending on runtime (Node serial / Node USB / Web Serial / WebUSB).

Install

npm install @emdzej/j2534-driver @emdzej/j2534-serial

Use (Node.js, serial transport)

import { J2534Device } from '@emdzej/j2534-driver';
import { createSerialTransport } from '@emdzej/j2534-serial';
import { Protocol, ConnectFlag } from '@emdzej/j2534-types';

const transport = await createSerialTransport(); // auto-detect OpenPort
const dev = new J2534Device(transport);
await dev.open();

const channel = await dev.connect(Protocol.ISO15765, 0, 500_000);
await dev.writeMsgs(channel, [{ data: Uint8Array.of(0x22, 0xf1, 0x90) }]);
const responses = await dev.readMsgs(channel, 1, 1000);
console.log(responses);

await dev.disconnect(channel);
await dev.close();

Slow-ECU support

Older K-line ECUs (BMW instrument cluster, IKE, body modules) read from EEPROM, which can take 50–200 ms before they start responding. The OpenPort 2.0 firmware silently drops responses that arrive after an internal short timeout unless the att transmit command carries an explicit timeoutMicros field — which the Tactrix reference DLL always emits. As of 0.2.0, passThruWriteMsgs propagates the J2534 Timeout argument into the firmware command (ms → µs, default 1 s for K-line). If your first exchange works but the second times out empty, this is the fix.

For DS2-style sessions, also enforce the SGBD's ParRegenTime host-side — wait regenTimeMs - elapsed ms before issuing the next TX. The firmware's J2534 P3_MIN handling appears insufficient for slow ECUs; host-side gating mirrors the Ds2Session pattern in @emdzej/ediabasx-interface-serial.

Debugging

J2534_RAW_TRACE=1 dumps every raw-byte chunk received from the device transport to stderr — useful for telling "device sent nothing" apart from "device sent a frame our K-line assembler dropped".

See also

• Root README — full project overview, supported hardware (Tactrix OpenPort 2.0 VID 0x0403 / PID 0xCC4D), and end-to-end examples
• @emdzej/j2534-types — the enum/interface declarations
• Transports: j2534-serial, j2534-usb, j2534-webserial, j2534-webusb

License

MIT