Power Grounds

The ME442 features multiple power ground pins. 

They should be earthed directly to the chassis. These allow current from the injectors, coils, DBW system and low-side switches to flow back to ground (battery negative).

Sensor Ground

All sensors should return to Pin 52 as a protected sensor ground.

Ignition 12V

Ignition 12V lines should be connected to a 12V (Ignition Live) line that becomes active on ignition only. Typically this would be fused as part of the EFI fusing at around 10-20A (dependant on amount of coils, outputs etc). No ECU settings will be lost during ECU power off/storage. The data-logging Date/Time clock is kept running by an internal battery backup (see below). Note you will NOT be able to connect to the ECU with MEITE without it being powered.

Be sure this supply line stays powered during cranking, as some ignition barrels do not! Always check for 12V when cranking if you seem to have issues starting.

Internal Battery

The ME442 houses an internal CR2032 battery (good for over 7 years) to keep the real-time-clock running even when the power is removed. This is used primarily for the engine log-book and datalogging time-stamp. Motorsport Electronics offers a replacement service for this battery.