ODB-II interfacing for Toyota

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ODB-II interfacing for Toyota

Hello everyone,
i am new here and have a very less information about the internal systems of a Car, so i want everyone of you to help me if possible.
recently i have started working on a project related to OBD-II of Toyota. i want interfacing with OBD-II of Toyota for data acquisition. how is it possible??? i have surfed different threads here and came to know about ELM323 and ELM327 ICs. Is it the very first and essential/ obligatory step to start with???
Plz help me, keeping me in mind as a beginner and try not to use too much technical language/terms.

Plz reply as soon as possible.

Gari.pk User 3167 asked on 01 Jul 2010 13:57:12 pm

1 Answer

420 views |

Muzammil - on 01 Jul 2010 13:57:42 pm

Bro, I am really not aware about OBD2 thingi. In honda's OBD1, you get direct TTL data from ECU, all you need to do is convert it into 232 via ic Max232. The protocol in HONDA OBD1's work like this:

To retrieve an instant value of a sensor, you send a specific HEX value via 232/ttl port, in return, the ecu will give you a value, you just need to calculate the result by a formula available on internet.

E.g I need Engine Coolent Temperature from ECU.

You will send 0x1A (Just giving example, don't remember exact value)
in return, ecu gives you answer 0x44... Now put this value in formula or implement it in your software and get the ECT of that instant.

similarly all sensor values can be retrieved, you need a loop that will send the values one by one to the ecu and retrieve the value and put it in formula and display the results in a GUI... all done!!!