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The ELM327 “OBD to RS232 Interpreter” IC introduced a new feature with v1.3 – the ability for a user to store a unique 12 character identifier code. This identifier can be read at any time, but it can not be changed once it has been set.

Software developers will have difficulty proving their code with this “write once, read many” feature, so we have introduced the ELM328 integrated circuit as a development tool for them.

The ELM328 is a special version of the ELM327 – it is identical electrically, but the firmware has one new command (AT @0) that resets the @2 identifier lock.


  • ELM327 code development only (not suitable for OBD scan tools)


  • Based on the latest version of the ELM327

  • Allows testing of the @2 and @3 functions

Connection Diagram

( PDIP or SOIC, top view )
ELM328 connection diagram

Usage Notes

  1. The ELM328 electrical connections and characteristics are identical to the ELM327 integrated circuit, so that it can be directly substituted into an ELM327 circuit.
  2. The ID string sent at power up, or in response to AT I is “ELM328 v1.4” and not “ELM327 v1.4”.
  3. The ELM328 offers one new AT command – the @0 command, which unlocks the @2 identifier, restoring it to the factory new condition. ELM327 software developers may repeatedly experiment with the @2 and @3 commands, using AT @0 to reset the identifier as required.
  4. The ability to send OBD commands has been removed from the ELM328. If you try to send an OBD command, the ELM328 will always act as if no ECU is connected, and no data will be transmitted.


The ELM328 data sheet (ver B, 14K):

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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 purchased (ELM328P + ELM328SM) for the calculation.


Select the desired integrated circuit package type, then the quantity desired, before adding it to your shopping cart. Quantity discounts will be applied as appropriate.

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Related Products

There are no related products – this is a special test device that is only useful for developing ELM327 and ELM329 software.