ELM-USB OBD2 Interface commands description

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Identification commands

ATI (device identification)

Returns fixed device identification

Example

>ATI
ELM327/ELM-USB v1.0 (c) SECONS Ltd.

Notice: Identification starts with "ELM32" in order to maintain compatibility with legacy applications.

AT/N

Retrieve ELM-USB unique interface serial number (ELM-USB specific, not part of ELM32x command set).

Example

>AT/N
xxxxxx

ELM-USB control commands

ATZ (reset)

Performs device reset and returns ELM-USB identification

Example

>ATZ
ELM327/ELM-USB v1.0 (c) SECONS Ltd.

ATWS (warm start)

Peforms "soft" reset and returns ELM-USB identification

Example

>ATWS
ELM327/ELM-USB v1.0 (c) SECONS Ltd.

ATPC (Protocol close)

Terminates current diagnostic session.

Example

>ATPC
OK

Communication set-up commands

ATD (set defaults)

ATLn (line feed enable/disable)

Usage: ATLn, where n is 0 or 1.

ATEn (echo on/off)

Usage: ATEn, where n is 0 or 1.

ATHn

Set "display headers" parameter.

Usage: ATHn, where n is 0 or 1.

Example data output with display headers turned off

>ath0
OK
>0100
41 00 BF DF B9 91

Example data output with display headers turned on

>ath1
OT
>0100
41 6B 10 41 00 BF DF B9 91 78

Protocol commands

ATST (set timeout)

Sets protocol timeout.

ATSP

Usage: ATSPn, where n is 0 to 9.

Set desired communication protocol.

0	Automatic protocol detection
1	SAE J1850 PWM (41.6 kbaud)
2	SAE J1850 VPW (10.4 kbaud)
3	ISO 9141-2 (5 baud init, 10.4 kbaud)
4	ISO 14230-4 KWP (5 baud init, 10.4 kbaud)
5	ISO 14230-4 KWP (fast init, 10.4 kbaud)
6	ISO 15765-4 CAN (11 bit ID, 500 kbaud)
7	ISO 15765-4 CAN (29 bit ID, 500 kbaud)
8	ISO 15765-4 CAN (11 bit ID, 250 kbaud) - used mainly on utility vehicles and Volvo
9	ISO 15765-4 CAN (29 bit ID, 250 kbaud) - used mainly on utility vehicles and Volvo

Example command for J1850 VPW

>AT SP 2
OK

ATTP (try protocol)

Usage: ATTPn, where n is 0 to 9.

Tries connection with selected protocol (protocol numbers are same as in ATSP).

Example command for J1850 PWM

>ATTP1
OK
>0100
41 00 BF DF B9 91

Example data output with incorrect protocol selected

>ATTP5
OK
>0100
BUS BUSY

ATDP (display protocol)

Usage: ATDP.

Returns currently used diagnostic protocol ("AUTO, protocol" if auto-detection is set)

>ATDP
AUTO, SAE J1850 PWM 

ATBD

Performs an OBD-II protocol buffer dump. Not to be used by applications.

Data commands

Communication is automatically established when this command is issued.

>0100
41 00 BF DF B9 91

Example data output with no ECU connected

>0100
UNABLE TO CONNECT

Notice: try setting ATSP0 (auto protocol detection) if you get this error.