car ECU data connection

Thread Starter


Joined Mar 25, 2021
I hope this post is in the right subsection and not too long

My issue is to do with a cars ECU and OBD related, I have a car with a Rover K series engine, OBDII was not a requirement before 2001 in the UK,. My car is a 2000 model year so not OBDII compliant

Later Rover cars had an ECU that is OBDII compatible MEMS 3, in my case mine is a MEMS1.9, this is not compatible with the OBDII diagnostic plug-ins, the MEMS1.9 has the same socket as an OBDII but totally different data so the two are not compatible with any OBDII in any way

But there are people who with their skill managed to write software that can communicate with the MEMS1.9 and extract quite a lot of data/information, I’ve been using a MEMS_Diag for some time works fine,

I had been testing out another diagnostic app for the MEMS1.9, Rover MEMS Diagnostic, these work on the Android OS and with a FTDI-based (FT232) 12V K-Line cable, commonly known as VAG-cable/VAG-KKL ( with a FTDI USB chip)

And an OTG USB cable

my Android tablet is able to communicate with the MEMS1.9 and extracts live data from the ECU

Now to my request

I’ve just come across another MEMS 1.9 app, the benefit of this app is it will work with my Mac, this app is called MemsFCR,

On their website it goes in to how to make up a able to communicate with the MEMS1.9 and my Mac, I am sure the description is for a plug not for my MEMS1.9 but an earlier MEMS

I am thinking, would the issue I’m having with this app not communicating between my Mac and the MEMS1.9 is I’ve not placed an OTG USB between the FTDI-based plug and my Mac as I do with the Android?

I have been told Mac’s have now a generic FTDI driver in the OS so I’m not keen on installing one from their link (unless I have to)

And little help will be very much appreciated as non of my car forum friends know of a solution


Joined Jan 30, 2016
I can't answer your specific query but I can tell you its nothing to do with the OTG cable - that's specific to phones and it allows the normally 'USB slave' phone to become a 'USB master'. The Mac is a USB Master by default but of course needs to know how to talk to the FTDI chip - thus it needs FTDI drivers, but whether Apples generic ones work with that software I couldn't say - but since that software supports both Mac & Windows its likely to use a generic serial port connection rather than something proprietary. If you have valid drivers loaded then the Mac should recognise the VAG cable when plugged in as a serial port though as I only use an old Windows laptop with VAGCom I can't help you with that. Having said that I read the description of the cable on that website and that's clearly for a non-OBD connector even though it supports v1.9. Which then suggests that although both cables support serial comms to the ECU maybe there's some other configuration that the VAG cable needs that the memsfcr software doesn't do. There's some info at that suggests there is some difference in the OBD socket wiring on certain cars that will stop the Mems software working with a VAG cable. There are so many variables here I cant help any further. Suggest you try and contact the developer of the Mac mems software (Colin?)