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.