ELM327 OBD2 pins requirements?

Hi all,

So to make sure I get all my PID's being read by Torque Pro I'm building my own ELM327 module based on the ELM327 v2.3 which is on it's way from Canada as we speak. I just want to double check with someone if my pinouts are correct for it to work?

I'll have pin 4 and 5 to GND, 6 CAN H, 14 CAN L and 16 +12V. So basically, just 5 pins (two grounds). So those pins are a given. Am I safe to miss out the ISO-9141-2 protocol and the J1850 protocol for the ELM327 circuit? It won't be used for communicating with anything else will it?

For the curious, the circuit I'm basing it on is found on page 84 of the official data sheet. The part of the circuit I'm not doing is underneath the ELM chip, pins 2 and 10 (J1850), and the part under the CAN circuit for pins 15 and 7 (ISO K and L respectively). I'm using a Microchip BM71 Bluetooth module and the recommended ADuM1201 logic level translator between them.

I'm doing all in SMD stuff too, I like a challenge!

I could have used the ELM329, but I don't know if Torque Pro would work the same. I haven't really looked into the technical differences as much. I might actually build a dedicated CAN one for my car and implement the low voltage stuff for the ELM329 and do the complete one for the ELM327. If I get this working, I might make a few more and sell them before ELM Electronics close down in 2022.

Any feedback would be appreciated. Thanks

 

I think the Torque Pro would use whatever protocol it find complete first, which would be the CAN in our case, I don't know if it would use the ISO9141-2 as well for reading extra PIDs.

It must be a Toyota thing for when they connect their expensive computer to the car to update the other buses, I think they have a LIN bus for the av/telematic stuff?

 

From what I understand, there are a lot of Chinese clones of the "original" ELM327 chipset because they initial version of the firmware was easily copied, but the later versions had copy protection features on them. The initial and copied version was 1.0 or 1.1. The clones are marketed at version 1.5, but now ELM Electronics have a version 2.3 of firmware written to the chipset. Mine arrived the other day from Canada. I'm literally laying out the board on Eagle as we speak. The chipset speak to ISO L and ISO K, J1850+ and CAN.