Package for communicating with a serial/usb OBD-II reader.

serial-obd 0.2.1

This version will only receive updates that were done in bluetooth-obd. On request I will update/sync this module with bluetooth-obd as this version is less-used.

Serial communication for OBD-II ELM327 devices.

This node module lets you communicate over a serial port with OBD-II ELM327 Connectors using Node.js.


  • Only tested on Ubuntu
  • Only tested with rfcomm, and not with actual serial port yet.
  • Only tested on ELM327 devices.
  • Not all OBD-II Commands are implemented yet.


  • If it's a Bluetooth ELM327, then it should already be paired and connected with rfcomm connect!
  • You might need to run it with SUDO! (If it says: serial port X is not ready!)


npm install serial-obd


var OBDReader = require('serial-obd');
var options = {};
options.baudrate = 115200;
var serialOBDReader = new OBDReader("/dev/rfcomm0", options);
var dataReceivedMarker = {};
serialOBDReader.on('dataReceived', function (data) {
    dataReceivedMarker = data;
serialOBDReader.on('connected', function (data) {
    this.startPolling(2000); //Polls all added pollers each 2000 ms. 


Emitted when data is read from the OBD-II connector.

  • data - the data that was read and parsed to a reply object

Emitted when the connection is set up (port is open).

  • data - the data that was read and parsed to a reply object

Creates an instance of OBDReader.

  • string portName Port that will be connected to. For example: "/dev/rfcomm0"

  • Object options Object that contains options, e.g.: baudrate, databits, stopbits, flowcontrol. Same options serialport module uses.

Find a PID-value by name.

  • name Name of the PID you want the hexadecimal (in ASCII text) value of.
  • string PID in hexadecimal ASCII

Parses a hexadecimal string to a reply object. Uses PIDS. (obdInfo.js)

  • string hexString Hexadecimal value in string that is received over the serialport.
  • Object reply - The reply.

  • string reply.value - The value that is already converted. This can be a PID converted answer or "OK" or "NO DATA".

  • string - The name. --! Only if the reply is a PID.

  • string reply.mode - The mode of the PID. --! Only if the reply is a PID.

  • string - The PID. --! Only if the reply is a PID.

Connect/Open the serial port and add events to serialport. Also starts the intervalWriter that is used to write the queue.

Disconnects/closes the port.

Writes a message to the port. (Queued!) All write functions call this function.

  • string message The PID or AT Command you want to send. Without \r or \n!
  • number replies The number of replies that are expected. Default = 0. 0 --> infinite

Writes a PID value by entering a pid supported name.

  • string name Look into obdInfo.js for all PIDS.

Adds a poller to the poller-array.

  • string name Name of the poller you want to add.

Removes an poller.

  • string name Name of the poller you want to remove.

Removes all pollers.

Writes all active pollers.

Starts polling. Lower interval than activePollers * 50 will probably give buffer overflows.

  • number interval Frequency how often all variables should be polled. (in ms) If no value is given, then for each activePoller 75ms will be added.

Stops polling.


This module is available under a Apache 2.0 license, see also the LICENSE file for details.