OBD Utils

The aim of this library is to provide utility methods to make it easier to work with the OBD-II protocol. This library only provides the interface/helper functions to make it easier to work with the protocol, and does NOT provides any bindings/transport to communicate with the underlying hardware.

A large part of the implementation is borrowed from EricSmekens's node-bluetooth-obd project.

CLI Usage:

# e.g. parse an OBD response
$ npx obd-utils parse "41 05 3C"
{
    "mode": "41",
    "pid": "05",
    "name": "temp",
    "unit": "Celsius",
    "value": 20
}

# e.g. get info for PID "05", i.e. engine temperature sensor
$ npx obd-utils info 05
{
    "mode": "01",
    "pid": "05",
    "bytes": 1,
    "name": "temp",
    "description": "Engine Coolant Temperature",
    "min": -40,
    "max": 215,
    "unit": "Celsius"
}

Programmatic Usage:

import { parseOBDResponse, getPIDInfo, getAllPIDs } from "obd-utils";

// Parse an OBD response
const parsedCommand = parseOBDResponse("41 05 3C");
console.log(parsedCommand);
/**
 * The resulting output will resemble:
 * IParsedOBDResponse {
 *      mode: '41',
 *      pid: '05',
 *      name: 'temp',
 *      unit: 'Celsius',
 *      value: '60'
 * }
 */

// Get the info for a PID
const info = getPIDInfo("0C");
console.log(info);
/**
 * The resulting output will resemble:
 * IObdPIDDescriptor {
 *      mode: '01',
 *      pid: '0C',
 *      bytes: 2,
 *      name: 'rpm',
 *      description: 'Engine RPM',
 *      min: 0,
 *      max: 16383.75,
 *      unit: 'rev/min'
 * }
 */

// List all PID IDs
const allPids = getAllPIDs();
console.log(allPids);
/**
 * The resulting output will resemble:
 * Array<IObdPIDDescriptor> [
 *    ...,
 *    {
 *       mode: '01',
 *       pid: '0C',
 *       bytes: 2,
 *       name: 'rpm',
 *       description: 'Engine RPM',
 *       min: 0,
 *       max: 16383.75,
 *       unit: 'rev/min'
 *    }
 * ]
 */

OBD2 PID reference table

Index PID Description Units 1 00 PIDs supported 00-20 Bit Encoded 2 01 Monitor status since DTCs cleared Bit Encoded 3 02 DTC that caused required freeze frame data storage Bit Encoded 4 03 Fuel system 1 and 2 status Bit Encoded 5 04 Calculated LOAD Value % 6 05 Engine Coolant Temperature Celsius 7 06 Short Term Fuel Trim - Bank 1,3 % 8 07 Long Term Fuel Trim - Bank 1,3 % 9 08 Short Term Fuel Trim - Bank 2,4 % 10 09 Long Term Fuel Trim - Bank 2,4 % 11 0A Fuel Pressure kPa 12 0B Intake Manifold Absolute Pressure kPa 13 0C Engine RPM rev/min 14 0D Vehicle Speed Sensor km/h 15 0E Ignition Timing Advance for #1 Cylinder degrees relative to #1 cylinder 16 0F Intake Air Temperature Celsius 17 10 Air Flow Rate from Mass Air Flow Sensor g/s 18 11 Absolute Throttle Position % 19 12 Commanded Secondary Air Status Bit Encoded 20 13 Location of Oxygen Sensors Bit Encoded 21 14 Bank 1 - Sensor 1/Bank 1 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 22 15 Bank 1 - Sensor 2/Bank 1 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 23 16 Bank 1 - Sensor 3/Bank 2 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 24 17 Bank 1 - Sensor 4/Bank 2 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 25 18 Bank 2 - Sensor 1/Bank 3 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 26 19 Bank 2 - Sensor 2/Bank 3 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 27 1A Bank 2 - Sensor 3/Bank 4 - Sensor 1 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 28 1B Bank 2 - Sensor 4/Bank 4 - Sensor 2 Oxygen Sensor Output Voltage / Short Term Fuel Trim V 29 1C OBD requirements to which vehicle is designed Bit Encoded 30 1D Location of oxygen sensors Bit Encoded 31 1E Auxiliary Input Status Bit Encoded 32 1F Time Since Engine Start seconds 33 20 PIDs supported 21-40 Bit Encoded 34 21 Distance Travelled While MIL is Activated km 35 22 Fuel Rail Pressure relative to manifold vacuum kPa 36 23 Fuel Rail Pressure (diesel) kPa 37 24 Bank 1 - Sensor 1/Bank 1 - Sensor 1 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 38 25 Bank 1 - Sensor 2/Bank 1 - Sensor 2 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 39 26 Bank 1 - Sensor 3 /Bank 2 - Sensor 1(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 40 27 Bank 1 - Sensor 4 /Bank 2 - Sensor 2(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 41 28 Bank 2 - Sensor 1 /Bank 3 - Sensor 1(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 42 29 Bank 2 - Sensor 2 /Bank 3 - Sensor 2(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 43 2A Bank 2 - Sensor 3 /Bank 4 - Sensor 1(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 44 2B Bank 2 - Sensor 4 /Bank 4 - Sensor 2(wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Voltage (ratio) 45 2C Commanded EGR % 46 2D EGR Error % 47 2E Commanded Evaporative Purge % 48 2F Fuel Level Input % 49 30 Number of warm-ups since diagnostic trouble codes cleared

50 31 Distance since diagnostic trouble codes cleared km 51 32 Evap System Vapour Pressure Pa 52 33 Barometric Pressure kPa 53 34 Bank 1 - Sensor 1/Bank 1 - Sensor 1 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 54 35 Bank 1 - Sensor 2/Bank 1 - Sensor 2 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 55 36 Bank 1 - Sensor 3/Bank 2 - Sensor 1 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 56 37 Bank 1 - Sensor 4/Bank 2 - Sensor 2 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 57 38 Bank 2 - Sensor 1/Bank 3 - Sensor 1 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 58 39 Bank 2 - Sensor 2/Bank 3 - Sensor 2 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 59 3A Bank 2 - Sensor 3/Bank 4 - Sensor 1 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 60 3B Bank 2 - Sensor 4/Bank 4 - Sensor 2 (wide range O2S) Oxygen Sensors Equivalence Ratio (lambda) / Current (ratio) 61 3C Catalyst Temperature Bank 1 / Sensor 1 Celsius 62 3D Catalyst Temperature Bank 2 / Sensor 1 Celsius 63 3E Catalyst Temperature Bank 1 / Sensor 2 Celsius 64 3F Catalyst Temperature Bank 2 / Sensor 2 Celsius 65 40 PIDs supported 41-60 Bit Encoded 66 41 Monitor status this driving cycle Bit Encoded 67 42 Control module voltage V 68 43 Absolute Load Value % 69 44 Fuel/air Commanded Equivalence Ratio (ratio) 70 45 Relative Throttle Position % 71 46 Ambient air temperature Celsius 72 47 Absolute Throttle Position B % 73 48 Absolute Throttle Position C % 74 49 Accelerator Pedal Position D % 75 4A Accelerator Pedal Position E % 76 4B Accelerator Pedal Position F % 77 4C Commanded Throttle Actuator Control % 78 4D Time run by the engine while MIL activated minutes 79 4E Time since diagnostic trouble codes cleared minutes 80 4F External Test Equipment Configuration #1 Bit Encoded 81 50 External Test Equipment Configuration #2 Bit Encoded 82 51 Fuel Type Bit Encoded 83 52 Ethanol fuel % % 84 53 Absolute Evap system Vapor Pressure kPa 85 54 Evap system vapor pressure Pa 86 55 Short term secondary oxygen sensor trim bank 1 and bank 3 % 87 56 Long term secondary oxygen sensor trim bank 1 and bank 3 % 88 57 Short term secondary oxygen sensor trim bank 2 and bank 4 % 89 58 Long term secondary oxygen sensor trim bank 2 and bank 4 % 90 59 Fuel rail pressure (absolute) kPa 91 5A Relative accelerator pedal position % 92 5B Hybrid battery pack remaining life % 93 5C Engine oil temperature °C 94 5D Fuel injection timing ° 95 5E Engine fuel rate L/h 96 5F Emission requirements to which vehicle is designed Bit Encoded 97 62 Actual engine - percent torque % 98 67 Engine coolant temperature Celsius 99 6B Exhaust gas recirculation temperature Celsius 100 6D Fuel pressure control system Celsius 101 6E Injection pressure control system Celsius 102 73 Exhaust pressure Celsius 103 78 Exhaust Gas temperature Bank 1 Celsius

LICENSE

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