ELM Electronics - OBD Products

Our "OBD Interpreter" integrated circuits are designed for use with vehicles that use one of the standard protocols, and that have an OBD or On Board Diagnostics connector. This data link connector (or port) is required on cars and light duty trucks as follows:

- 1996 or newer North American vehicles
- 2001 or newer European Union gasoline vehicles
- 2004 or newer European Union diesel vehicles
- 2006 or newer Australian vehices

as well as many others throughout the world. If your vehicle is older than this, it may still have a connector that looks the same, but does not adhere to one of the standard protocols. Before buying one of our circuits, be sure to check that your vehicle does in fact use an OBD protocol. For more information on these standards, refer to our reference pages.

Often, we are asked for circuit boards, J1962 connectors, or more user-friendly software to use with our ICs. Unfortunately we only sell the ICs and none of the support hardware or software. Please refer to our reference pages for links to companies that provide this support.

Elm Electronics currently offers five different OBD Interpreter integrated circuits. They are as follows:

ELM320 - OBD (PWM) to RS232 Interpreter Data Sheet

320 The ELM320 allows you to talk to your 41.6KHz J1850 PWM OBD (On Board Diagnostics) equipped vehicle through a standard RS232 serial connection, using only simple ASCII commands. This updated version remains just as easy to use, but is now completely programmable, allowing even more control, and of course possibilities.
As before, the user need only issue the desired commands - the data formatting, error checking, bus arbitration, etc. is all handled by the ELM320. If you presently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old (the only difference at power-up is that linefeeds are now on by default). Simply unplug the old and plug in the new.
This IC only supports the 41.6KHz J1850 PWM data format which is typically used in Ford Motor Company vehicles. If you have a different vehicle, please refer to our ELM322 and ELM323 products. (100K)

Available in: 8-pin PDIP $16.50 CDN, 8-pin SOIC $18.50 CDN

ELM322 - OBD (VPW) to RS232 Interpreter Data Sheet

322 Similar to the ELM320, and also completely revised, the ELM322 is for connecting to an OBDII equipped vehicle which uses the 10.4KHz J1850 VPW format. This standard is typically used in General Motors Corporation and some DaimlerChrysler vehicles. The user need only issue the desired commands through an RS232 serial connection and the data formatting, error checking, bus arbitration, etc. on the vehicle side is all taken care of by the ELM322. This allows experimenters to inexpensively create their own 'scan tool'. If you presently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old, so you can simply replace your IC if you want to upgrade.
(116K)

Available in: 8-pin PDIP $16.50 CDN, 8-pin SOIC $18.50 CDN

ELM323 - OBD (ISO) to RS232 Interpreter Data Sheet

323 The ELM323 completes our trio of OBDII ICs, allowing you to talk to your ISO 9141-2 or ISO 14230-4 standard OBDII equipped vehicle using an RS232 serial connection. It transparently converts between a 10.4KHz ISO data stream and standard ASCII characters, allowing trouble codes and operating parameters to be easily retrieved without the need for special software. No knowledge of data formatting, error checking, bus initiation etc. is needed either, as the ELM323 handles all of it for you.
The present version of the ELM323 (v2.0) provides several programmable features that the previous versions did not offer. It now allows programmable header bytes, adjustable timeouts, the ability to report in the packed data mode, and offers a special monitoring mode as well. This is in addition to all of the capabilities that the v1.x ICs offered - the full seven byte command structure, two line (K and L) initiation, software selectable linefeeds and character echoing, and the visual feedback provided by the four LED outputs.
If you currently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old, so you can simply replace your present IC with one of these, and immediately begin enjoying these new features.
(125K)

Available in: 14-pin PDIP $17.50 CDN, 14-pin SOIC $19.50 CDN

ELM327 - OBD to RS232 Interpreter Data Sheet

327 We've improved our best OBD Interpreter, so now it's even better!
The new ELM327 v1.3 IC has taken the proven v1.2, added more error monitoring and recovery, added several more AT commands, has improved the CAN printing, and has added a few features that many of you have been asking for. To name just a few of the new features, you can now:

set the maximum number of responses to obtain

remove spaces from ECU responses (to speed data transmission)

store a unique identifier in EEPROM

set the CAN mask and filter with one command

easily switch between variable and fixed CAN message lengths

send CAN remote frames (RTRs)

The IC has been well-tested to date, with some very favourable responses. We think that you will be pleased as well. Download either the 'QuickSheet' (a 6 page summary), or the full (59 page) Data Sheet for a more complete description of the new ELM327.

The new ELM327 still converts OBDII data (ISO 15765-4 CAN, SAE J1850 PWM, SAE J1850 VPW, ISO 9141-2, ISO 14230-4 and SAE J1939) for you - we've just made it better, with no increase in the price!
We are currently shipping version 1.3a of this IC.
(261K)

QuickSheet

(29K)

Available in: 28-pin PDIP $32.50 CDN, 28-pin SOIC $32.50 CDN

ELM328 - OBD Device Identifier Test IC Data Sheet

327 The ELM328 IC is electrically identical to the ELM327 except that it offers one new AT command which can be used to reset the @2 Device Identifier lock. This provides code developers with a means to repeatedly test code which writes to the @2 device identifier, without requiring a new IC each time.
Note that the ELM328 supports all of the ELM327 AT Commands, but will not transmit OBD messages - it is for code development only, and not for use in scan tools.
(16K)

Available in: 28-pin PDIP $32.50 CDN, 28-pin SOIC $32.50 CDN

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ELM320 - OBD (PWM) to RS232 Interpreter		Data Sheet
	The ELM320 allows you to talk to your 41.6KHz J1850 PWM OBD (On Board Diagnostics) equipped vehicle through a standard RS232 serial connection, using only simple ASCII commands. This updated version remains just as easy to use, but is now completely programmable, allowing even more control, and of course possibilities. As before, the user need only issue the desired commands - the data formatting, error checking, bus arbitration, etc. is all handled by the ELM320. If you presently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old (the only difference at power-up is that linefeeds are now on by default). Simply unplug the old and plug in the new. This IC only supports the 41.6KHz J1850 PWM data format which is typically used in Ford Motor Company vehicles. If you have a different vehicle, please refer to our ELM322 and ELM323 products.	(100K)
	Available in: 8-pin PDIP $16.50 CDN, 8-pin SOIC $18.50 CDN

ELM322 - OBD (VPW) to RS232 Interpreter		Data Sheet
	Similar to the ELM320, and also completely revised, the ELM322 is for connecting to an OBDII equipped vehicle which uses the 10.4KHz J1850 VPW format. This standard is typically used in General Motors Corporation and some DaimlerChrysler vehicles. The user need only issue the desired commands through an RS232 serial connection and the data formatting, error checking, bus arbitration, etc. on the vehicle side is all taken care of by the ELM322. This allows experimenters to inexpensively create their own 'scan tool'. If you presently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old, so you can simply replace your IC if you want to upgrade.	(116K)
	Available in: 8-pin PDIP $16.50 CDN, 8-pin SOIC $18.50 CDN

ELM323 - OBD (ISO) to RS232 Interpreter		Data Sheet
	The ELM323 completes our trio of OBDII ICs, allowing you to talk to your ISO 9141-2 or ISO 14230-4 standard OBDII equipped vehicle using an RS232 serial connection. It transparently converts between a 10.4KHz ISO data stream and standard ASCII characters, allowing trouble codes and operating parameters to be easily retrieved without the need for special software. No knowledge of data formatting, error checking, bus initiation etc. is needed either, as the ELM323 handles all of it for you. The present version of the ELM323 (v2.0) provides several programmable features that the previous versions did not offer. It now allows programmable header bytes, adjustable timeouts, the ability to report in the packed data mode, and offers a special monitoring mode as well. This is in addition to all of the capabilities that the v1.x ICs offered - the full seven byte command structure, two line (K and L) initiation, software selectable linefeeds and character echoing, and the visual feedback provided by the four LED outputs. If you currently use one of our v1.x ICs, you will be pleased to know that this version (v2.0) is pin-compatible with the old, so you can simply replace your present IC with one of these, and immediately begin enjoying these new features.	(125K)
	Available in: 14-pin PDIP $17.50 CDN, 14-pin SOIC $19.50 CDN

ELM327 - OBD to RS232 Interpreter		Data Sheet
	We've improved our best OBD Interpreter, so now it's even better! The new ELM327 v1.3 IC has taken the proven v1.2, added more error monitoring and recovery, added several more AT commands, has improved the CAN printing, and has added a few features that many of you have been asking for. To name just a few of the new features, you can now: set the maximum number of responses to obtain remove spaces from ECU responses (to speed data transmission) store a unique identifier in EEPROM set the CAN mask and filter with one command easily switch between variable and fixed CAN message lengths send CAN remote frames (RTRs) The IC has been well-tested to date, with some very favourable responses. We think that you will be pleased as well. Download either the 'QuickSheet' (a 6 page summary), or the full (59 page) Data Sheet for a more complete description of the new ELM327. The new ELM327 still converts OBDII data (ISO 15765-4 CAN, SAE J1850 PWM, SAE J1850 VPW, ISO 9141-2, ISO 14230-4 and SAE J1939) for you - we've just made it better, with no increase in the price! We are currently shipping version 1.3a of this IC.	(261K) QuickSheet (29K)
	Available in: 28-pin PDIP $32.50 CDN, 28-pin SOIC $32.50 CDN

ELM328 - OBD Device Identifier Test IC		Data Sheet
	The ELM328 IC is electrically identical to the ELM327 except that it offers one new AT command which can be used to reset the @2 Device Identifier lock. This provides code developers with a means to repeatedly test code which writes to the @2 device identifier, without requiring a new IC each time. Note that the ELM328 supports all of the ELM327 AT Commands, but will not transmit OBD messages - it is for code development only, and not for use in scan tools.	(16K)
	Available in: 28-pin PDIP $32.50 CDN, 28-pin SOIC $32.50 CDN