RS232 on the Mini - Any way around needing the Rx connected?

I’m setting up my new mini to communicate with a Nissan ECU via Consult. For whatever reason, the ECU sends data out via open collector and receives it via RS232. So long story short it doesnt provide the Rx line that is required for the onboard RS232 on the mini to work.

I’m able to us an external RS232 chip to transmit through from a com pin but I’d obviously prefer to use the built in RS232 function on the Mini. Is anyone aware of a way to get the built in RS232 working with without the Rx being hooked up that would be easier than using an external RS232 chip?

Thank you,

Use 2 com ports one for transmit using the rs232 and the other to receive using ttl levels by using a pull up to 3.3v on your open collecto output…

Or you could use the same and remap the rx to another pin…