ARC2 Wiring Diagram
presented by Jeff Lucius
This diagram is for the first version of the ARC2-GP, which I have. Some later models require the yellow wire from the ARC2 to be connected to a +12V power source (such as the ARC2 red wire), rather than the IPS pin on the ECU. On these newer models, the ACCEL is a fine-tune adjustment for LOW. For 1994+ 3S cars, add 20 to the ECU pin numbers (note that ECU wire colors may be different also). Consult the wiring diagram that should come with your unit for exact connection instructions. Tips for getting to the ECU and tapping ECU wires can be found on my web pages 2-safcii-instal.htm and 2-arm1instal.htm.
After I installed the ARC2 (and the S-AFCII and ARM1, which also tapped into the ECU wires) I became aware of a very handy patch harness built by Autosport Wiring specifically for our cars (and many others). They want $139 for 1990-1993 ECUs and $159 for 1994-1998 ECUs. The patch harness plugs between the ECU and the factory harness. All taps can be made into this patch harness and so the car can be returned quickly to original condition or the patch harness modified for other equipment. Pretty neat, if a bit expensive. For some harnesses Autosport Wiring has highlighted some commonly tapped wires like RPM, TPS, injector 1, etc. If you decide to use one of these handy harnesses, the instructions below can still be followed, except you will be working on the patch harness rather than the factory harness.
Page last updated December 19, 2004.