The "ELM327 v1.3a" is the addition to the OBD family, providing CAN (ISO 15765-4) support, as well as SAE J1850 PWM, SAE J1850 VPW, ISO 9141-2 and ISO 14230-4. ELM Electronics actually taken the best of the ELM320, the ELM322, and the ELM323, improved on them and then added seven CAN protocols.

Just as with the other ICs, the ELM327 transparently converts OBDII data into 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 ELM327 handles all of it for you. You don't even need to know what protocol your car 'speaks', as this IC automatically detects that for you, too.

In addition to the protocols, we think that you will also enjoy some of the enhancements. For example, the RS232 interface has been completely updated. It is now a background task so it doesn't interfere with OBD receives, it has a large data buffer to allow for fluctuations in the OBD data, and it offers a second baud rate (115.200 for RS232, 500.000 for USB).


QuickSheet for "ELM327 v1.3a " from ELM Electronics.
DataSheet for "ELM327 v1.3a " from ELM Electronics.

ELM327 Features...
The Special-Chip "327 v1.3a" from ELM Electronics offers many features that make OBD interfacing easier:

• 12 supported protocols in v1.3a, with variations
  - SAE J1850 PWM (41.6 Kbaud)
  - SAE J1850 VPW (10.4 Kbaud)
  - ISO 9141-2 (5 baud init, 10.4 Kbaud)
  - ISO 14230-4 KWP (5 baud init, 10.4 Kbaud)
  - ISO 14230-4 KWP (fast init, 10.4 Kbaud)
  - ISO 15765-4 CAN (11 bit ID, 500 Kbaud)
  - ISO 15765-4 CAN (29 bit ID, 500 Kbaud)
  - ISO 15765-4 CAN (11 bit ID, 250 Kbaud)
  - ISO 15765-4 CAN (29 bit ID, 250 Kbaud)
  - SAE J1939 CAN (29 bit ID, 250* Kbaud)
  - USER1 CAN (11* bit ID, 125* Kbaud) [default settings, user adjustable]
  - USER2 CAN (11* bit ID, 50* Kbaud) [default settings, user adjustable]
• Standard ascii characters used for all commands and responses
• User settable CAN mask and filter values
• Programmable Headers
• Up to 115.200 baud for RS232 communication, 500.000 baud for USB
• Ability to bypass the initiation process and force a protocol to become active
• Ability to close a protocol at any time
• Hardware handshaking signals to simplify computer interfaces
• Ability to manually select any of the supported protocols
• Last successfully initiated protocol can be automatically stored in EEPROM
• Voltage input allows monitoring of the vehicles charging system
• Voltage input is easily field calibrated
• Brownout protection protects against problems from low voltages
• Responses can be factory programmed for other languages
• Special @1 string allows unique identifiers for larger Customers
• Standard RS232 pin polarities
• Busy output, RTS input for RS232 handshaking
• Can send 8 byte OBD messages
• Buffered RS232 sending (256 byte)
• Schmitt trigger OBD inputs simplify interface in a noisy environment
• Buffer Dump command displays OBD messages as sent or received
• ISO 9141/14230 wakeup string (idle message) is fully programmable
• Warm Start command provides a quick system reset alternative