That's a very specific process where the level check can only be done at a certain temperature..........which the car blows past quickly.
Short time window.
Supposedly, procedure on 2025 Civic is as follows, with tools including an obd2 scanner. Caveat: I haven't done it in person, and I didn't check this vs. the 2025 Civic service manual. This is just what I read. So folks should do their own research. For example, 2025 Civic has different transmissions on different models. This is supposedly for the CVT transmission.
Warm up
- Drive car 5 minutes to get trans fluid warmed up
Get access
- Jack up car on 4 jack stands to get it level
- Remove splash shield
- Check trans case temp to make sure it is warm but not too hot to hold hand on
Drain fluid
- remove fill plug
- remove check plug
- remove drain plug and drain fluid
- wipe off magnetic tip of drain plug
- use new crush washer on drain plug
- reinstall drain plug and torque it
Put in new fluid
- fill through fill port until fluid drips from check port
- wait for any flow from check port to slow to drips
- replace check plug
- replace fill plug
Get to temp
- Plug in obd2
- Start car with foot on brake
- Keep foot on brake throughout
- Shift through p-r-n-d (about 2-5 seconds at each spot) and back to p
- Cycle through that shifting process every 5 minutes until obd2 shows trans fluid at 55c.
Fine-tune level
- Turn off engine
- Remove fill plug
- Remove check plug
- Put in trans fluid until some drips out of check port
- Wait for flow from check port to be drips (not a stream)
Button up
- Put new crush washer on check plug, reinstall check plug, torque it
- Reinstall fill plug
- Reinstall splash plate
- Unjack car