The Orion TCU is a universal controller designed for most types of Optic, Hall or Magnetic reluctor sensors. It can read 2 sensors in total. Mostly Crank or RPM signal from ECU, and Speed sensors from transmission.

The drawings are based on the OT01 – P1 and OT02 – P1 harnesses. Take care to keep wires screened as close to the sensor as possible. Do not route sensitive input harnesses with HV leads or switching inductive loads. This will induce spikes in the sensor lines and confuse the TCU on what is the real signals.

The Red parts in the drawing are not always needed but if you do get interference on speed or RPM readings then you may add these components as filters to clean the signals up.

Common mistakes installers make in connecting ECU and TCU signals is that the Earth point is not on the same voltage level. As all the signals are referenced to earth this will make problems.

OT02 – P1 is for standalone applications like diesels where there is no ECU available. Here the TPS and RPM sensor is made with screened wires that brings power and earth to the sensor.

OT01 – P1 harness is made to use with ECU systems. The TPS and RPM lines are single wires and made to connect to the ECU signals. Mercury2 or Orion ECU’s already have the Green RPM output wire and Yellow TPS output wire for easy installations. These wires can be connected together.

Below are links to the connection diagrams of the different sensors. Note that RPM connections differ between the 2 harnesses.

Speed Sensor Wiring
RPM Sensor Wiring OT01-P1
RPM Sensor Wiring OT02-P1 Stand Alone