Motec M4 Aux V and Aux T inputs

Discussion and support for MoTeC's earlier generation ECUs

Motec M4 Aux V and Aux T inputs

Postby xuzle on Sun Feb 02, 2020 1:56 am


I have a gold box M4 wich i'm running in my e30 drift car with M50b25 turbo engine. Im currently wanting to wire in the aux t and aux v input to use for boost/ignition compensation and possibly to stage revlimit (via clutch operated switch)

But my question is, could i use 12v thru a switch and to the aux t and v inputs or do I need to use 5v as the manual says? Or can one of the inputs or borh be switched to ground?

I tried searching but could not find anything supporting or denying if it is possible to switch from 12v source

I'm currently in to wire the aux v from +12v and ground through a rotary switch and in to the ecu.
And then use the clutch switch with 12v in to the aux t input.

The reason to why I'm asking is that it's a lot easier for me to wire in 12v than splitting my ecu harnes to get 5v out to these two switches.

Posts: 1
Joined: Sun Jan 26, 2020 4:44 am

Re: Motec M4 Aux V and Aux T inputs

Postby SprinterTRD on Mon Feb 03, 2020 1:07 pm

Aux V and Aux T cannot be used with 12V.

Aux T has a internal pull-up resistor to 5V that can be used with 2 wire resistive sensors. IE temperature sensor.
Aux V is for sensors that output a voltage. IE Map sensor.
The two inputs can only read a voltage between 0 and 5V. From memory will go into error if 0 or 5V is input.

Digital input 1 and 2 have internal pull-up resistors to 5V and need to be grounded to activate.
Pro User
Posts: 354
Joined: Wed Jul 16, 2008 8:24 am

Return to M4 and M48 ECUs (including M2R and MLS variants)

Who is online

Users browsing this forum: No registered users and 1 guest