I am using those Routines!
But, should be good have it to BASIC ESP8266
In that github examples, the channel to send commands and get answer is the "Serial"
If you port it to BASIC, should be to good you have the possibility to have too a "TCP" channel , because there are OBD2 wifi 802.11 modules too.
You connect directly to OBD2 WIFI MODULE and get access to OBD2 AT commands using TCP channel.
If you use OBD2 BLUEOOTH or RS232 OBD2 modules, use the Serial