Rollover Sensor Input or Power adding switch input Tacho (RPM) or Toggle signal when MAP is read or Output of TPS duty cycle signal to second ECU (4 cylinder engines) O2 heater B or AC cooling fan relay or Head light relay or Second air injection valve MIL Lamp or Misfire generation status of cylinder 1 PinĮCP valve or Start motor disable relay or AC cooling fan relay or Head light relay or Second air injection valve Some pins may also be configured for testing purposes. Implementing full flashing support (calibration upload / download / editing) is a huge work of an entire year for each new ECU model.