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Old 06-27-2012, 04:40 PM   #3 (permalink)
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Join Date: Jun 2012
Location: Los Angeles
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Today. I made MPGunio finally work with the modified ELM327 OBD-II USB adapter bought frome Amazon.
If you want use this $20 usb adapter work with your Arduino. You need do following modifications.

ELM327 adapter:
Disconnected the PIC18F2480 pin17, pin18 from PCB. Then, connect pin17(Tx) to Arduino Rx(0), pin18(Rx) to Arduino Tx(1). Also connect the pin19 from the PIC18F2480 to the Arduino Gnd.
PIC18F2480 ---------------- Arduino
pin17(Tx) ------------------ Rx(0)
Pin18(Rx) ------------------ Tx(1)
pin19 ---------------------- Gnd

OBDunio32K Code:
(1) Uncomment the "#define ELM"
(2) Comment the "#define useECUState"
(3) Change "Serial.begin(9600)" to "Serial.begin(38400)".
else if(str[1]=='3') // ISO 9141
elm_command(str, PSTR("ATSH6810F1\r"));
== Change to: ==
else if(str[1]=='3') // ISO 9141
elm_command(str, PSTR("ATSH686AF1\r")); // "6810F1"

BTW, My car is 2004 Honda S2000, If the code(4) don't work on your car. Change "6810F1" to "6810F0" and give a try.

Last edited by SuperCharger; 06-27-2012 at 04:49 PM..
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