You'll want it any time you're wiring an Elite 550 with the basic universal harness into a car: identifying which labelled lead goes to injectors, coils, sensors and power, planning where to run the loom, and tracing a fault later.
What to check as you work through it:
- Power and ground wires go to the right places, with the ECU ground going to a clean chassis or engine point.
- Injector and ignition outputs are in firing order, matching how you'll set them up in ESP.
- Sensor grounds go back to the ECU's sensor ground, not the chassis.
- Any lead you don't use is insulated and tied back.
Running the premium loom instead? See the premium harness diagram, and the complete Elite 550 pinout for pin-level detail.
Need this diagram? Ask us and we'll send it over with advice for your build.
