ELM327 v1.3a

OBD to RS232 Interpreter – firmware version 1.3a
This older product remains available because of continued demand.

Quantity Pricing

The following are the unit prices, as you vary the quantity purchased:






All prices are in Canadian dollars. We use the total number of ELM327 v1.3a ICs purchased (327P_V13 + 327SM_V13) for the calculation.


Almost all new automobiles produced today are required, by law, to provide an interface from which test equipment can obtain diagnostic information. The data transfer on these interfaces follow several standards, none of which are directly compatible with PCs or PDAs. The ELM327 is designed to act as a bridge between these On-Board Diagnostics (OBD) ports and a standard serial interface.

The ELM327 builds on improved versions of our proven ELM320, ELM322, and ELM323 interfaces by adding seven CAN protocols to them. The result is an IC that can automatically sense and convert the most common protocols in use today. There are a number of other improvements as well – a high speed RS232 option, battery voltage monitoring, and customizable features through programmable parameters, to name only a few.

The ELM327 requires few external components to make a fully functioning circuit. The data sheet discusses the interface details, and show how to use the IC to ‘talk’ to your vehicle, then concludes with two schematics to get you started.

If you are wondering what the differences are between the many ELM327 versions, you may find the Version History section in Help / OBD / Tips to be helpful.


  • Diagnostic trouble code readers
  • Automotive scan tools
  • Teaching aids


  • Supports 12 protocols
  • RS232 baud rates to 500Kbps
  • Automatically searches for protocols
  • Fully configurable with AT commands
  • Voltage input for battery monitoring
  • Low power CMOS design

Connection Diagram

( PDIP or SOIC, top view )
ELM327 v1.3a connection diagram

Block Diagram

ELM327 v1.3a block diagram


The ELM327 v1.3a data sheet (261K):

pdf icon

Alternative Labelling

To help us meet demand, Microchip Technology has been programming and labelling some of the ELM327SM chips for us. These ICs may look different, but are functionally identical. You may receive ICs that look like those shown above, or as shown below. The differences are only in appearance:

sku: 327SM_V13

Related Products

The following offer more advanced versions of the ELM327 firmware:

And you may find it convenient to order CAN transceivers from us: