Memory dump of ECU

[Trevor]

Originally Posted by b3lha

That is bad news. As the binary bits are coming down the wire, the converter is seeing a 1 (2 volts to 5 volts) when it should be seeing a 0 (0 volts to 0.8 volts).

I wonder if the signal voltage from the ECU is too high?

Or is your input impedance/loading too low i.e. too sensitive. A higher relative loading would pull down the output/input signal voltage. This could be where the Subaru OEM monitor differs. The fact that you indicate that a zero voltage is not being recorded, points in this direction.

The lower the monitor input impedance/resistance; the greater the signal current; lower the voltage (Dependent on output capacity) and greater the immunity to noise. In all respects the transmitted signal is more robust, a worthwhile feature.

In other words, the existing signal could be overloading your gear. Think of the affect of overloading the input of an audio amp.