To prep the SC for the GTE swap, I’ve sourced a MT GTE ECU and a Aristo ( JDM 2JZGTE ) engine harness. For those doing this swap into a SC300, the wiring is a lot easier than the typical S-Chassis wiring in that many of the vehicle’s functions and wires are the same.
Given the similarities between the SC300 and the MKIV Supra, this is really no surprise, however you will need to lengthen and extend the third plug or body plug as well as rewire.
This body plug disconnects from the sc300 along the firewall, next to the ABS module and near the windshield.
Upon splicing open this harness, you will notice many similarities with your Aristo harness. The large connector on this harness connects to the SC300 body plug and also the small plug that leads to the ECU.
For ease of wiring installation, we are eliminating the following wires (Traction Control D17, Pressure sender ( Dummy Light ) D10, and Transmission Shift indicator D1)
Use the following pinout and match the corresponding colors accordingly.
The Aristo harness and ecu plugs :
For a pin by pin how to, refer to this chart here :
Now with your engine harness properly wired, you may now remove your old SC300 harness and install your GTE ECU and plug it in. Next up, we start yanking weight in preparation of motor swap, as well as installing a new Cometic head gasket, ARP head studs and selecting our turbo setup.