The early system up until 1995 was the ODB system, it used a different style port than the newer OBDII port that came out in 1996 and up like your vehicle has. A common reason for a scan tool to not read is a lack of power or ground on the OBDII port. The problem with Honda is that they didn't make the port to the full standard, so some scan tools won't work on them.
To use a scan tool with them you use an external power source like a power adapter to power the scan tool, so it doesn't look for power from the car. The other option is to add the correct pins into the connector to provide the power and ground connections in the port.
I've done that a few times for damaged or like your vehicle where the pins are missing.
There is no fuse to replace to get the power there as the actual pin is missing. Repairing it would take adding those pins or making an adapter harness that includes the missing pins.
Attached is the common pinout for the OBD II port. If you compare it to the wiring yours shows you can see the differences. Yours is missing the ground at pin 5 and the power at pin 16. It's likely that if you added those pins into your connector that the scan tools they are using would work.
Tuesday, June 7th, 2022 AT 7:05 AM