OBD 1 not 2

Ok I am attempting to tap into the great mp3car hardware collective.

I have a 1994 Dodge Ram Van B250 360CI. It uses OBD 1 for it's engine management.

I have found the diagnostic connector under the cowl inside the engine compartment.

I have determined the pin out using my multi-meter and have determined the data feed seems to be serial.

I am versed in programming and serial interfacing.

What I am looking for is information on how to physically tie a PC into this diagnostic port and deciphering it's data.

I know it can be done but Google does not reveal much information on the subject.

Thanks in advance! Any insight will be appreciated! :nutz:

Have a look at what RobbyBMW did with the TPMS project, you'll probably need to go through the same sort of process.

Anyone, hitting road blocks on Google.

Hi,
Sorry for my bad English.
I live in Thailand and own VW Transporter T3 Syncro which run on SUBARU EJ25 JDM. Ofcause, it is OBD I.
It took me for a while and I found the solution at last.

See this link.
http://www.surrealmirage.com/vrg3/b10scan/
this describe the pinout

for schematic , follow this link
http://www.vwrx.com/index.php?pg=selectmonitor

then hunt for :
RS232-Discrete Schematic Rev B
RS232-Integrated Schematic Rev B

I've tested Integrated one and it work so fine. This schematic convert +12 Volt signal from ECU to TTL +5V which computer can be used. Ofcause, it can be connected to SerialToUSB device if your "car pc" doesn't has serial interface.
A hint : if you manage to wire them for yourself. Keep in mind that you need to put this "converter" close to your pc to increase Signal to Noise Ratio before the data "unreadable".

You may download their software and run "SelectMonitorDump utility" which readout and display "any" range in ECU memory as HEX. BTW, you need to set correct serial protocal such as BaudRate for example to talk to your ECU.

However , the matter is how to "find" the right data and "interpret" that data into understandable values. That's the pain ITA.

Quote:

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Originally Posted by Hanniboon

Hi,
Sorry for my bad English.
I live in Thailand and own VW Transporter T3 Syncro which run on SUBARU EJ25 JDM. Ofcause, it is OBD I.
It took me for a while and I found the solution at last.

See this link.
http://www.surrealmirage.com/vrg3/b10scan/
this describe the pinout

for schematic , follow this link
http://www.vwrx.com/index.php?pg=selectmonitor

then hunt for :
RS232-Discrete Schematic Rev B
RS232-Integrated Schematic Rev B

I've tested Integrated one and it work so fine. This schematic convert +12 Volt signal from ECU to TTL +5V which computer can be used. Ofcause, it can be connected to SerialToUSB device if your "car pc" doesn't has serial interface.
A hint : if you manage to wire them for yourself. Keep in mind that you need to put this "converter" close to your pc to increase Signal to Noise Ratio before the data "unreadable".

You may download their software and run "SelectMonitorDump utility" which readout and display "any" range in ECU memory as HEX. BTW, you need to set correct serial protocal such as BaudRate for example to talk to your ECU.

However , the matter is how to "find" the right data and "interpret" that data into understandable values. That's the pain ITA.

---

Thank you very much sir!