OBD k line serial interface

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Frank Richards
Posts: 3
Joined: Tue Jan 12, 2016 9:21 pm

OBD k line serial interface

Post by Frank Richards » Wed Jan 13, 2016 5:24 pm

Hi guys,

First post here so hello and thanks for providing a great forum!

I am after some advice on a home/auto project I am currently trying to get up and running.

I am trying to read the data transmitted from a plug in OBD tool which uploads certain commands/instructions to the vehicles ecu.

The onboard MCU is an STC11 series chip, data is sent via the K Line via the OBD socket.

What I want to do is read the data transmitted down the K Line, so I need what I think is a serial interface and some software to decipher it? My theory is that I can connect to the relevant pin on the tools OBD connector, supply 12v, then read the data stream? Question is what hardware & software do I need to do this? Bus pirate maybe?? Or a simple serial interface?

I'm trying to understand what the tools transmits with regards to code and how this will work on various vehicles, from there I want to understand and if it is possible to re programme the unit its self to carry out other functions/instructions to the ecu.

Sorry if this is a bit vague or if it is even possible in the first place, I will answer any question you may have, any help appreciated

Thanks again

frank

piratepaul
Posts: 432
Joined: Mon May 20, 2013 2:45 pm

Re: OBD k line serial interface

Post by piratepaul » Sat Jan 16, 2016 12:02 pm

I am not sure what the K line is.
If you search ECU remapping on eBay there is lots of software available, connectors for the laptop etc.
I have not used it but would be interested to find out how you get on.

Tar&stuff.

Frank Richards
Posts: 3
Joined: Tue Jan 12, 2016 9:21 pm

Re: OBD k line serial interface

Post by Frank Richards » Sat Jan 16, 2016 12:45 pm

k line is the data channel used, which I think is serial possibly?

Pauldf
Posts: 170
Joined: Mon Jun 10, 2013 7:42 pm

Re: OBD k line serial interface

Post by Pauldf » Sun Jan 17, 2016 4:04 pm

Even if it is serial, unless you know the protocol and how to decipher it then you'll just end up with a hell of a lot of 0s and 1s!

Frank Richards
Posts: 3
Joined: Tue Jan 12, 2016 9:21 pm

Re: OBD k line serial interface

Post by Frank Richards » Sun Jan 17, 2016 5:25 pm

The protocol is j1850

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