What does these error codes mean? p0401 p0730 p1751

My car is giving extreme transmission problems and seems like i need to check with a mechanic just tomorrow. The transmission gave up on my way back from office. I had to drive it back home at 40mph max. And after I reached home the car won't reverse as when i move the car in reverse gear - it doesn't engage the car. I then tried gear 2 and 1 -- and then moved it back to R - thats where it actually started to reverse.

The error codes that I get from my obd2 reader are

p0401, p0730, p1751


I got this car almost 1.5 years ago from some guy on craigslist - carfax looked fine at that time. It had 126K miles and now has 140k miles on it but i have no idea when was the transmission fluid changed last time. Recent inspection 3 months ago went fine with the mechanic telling me car is in "good shape" -- Can changing the fluid fix the problem or do I need to prepare for a big bill ?

most likely transmission is bad, known problem in accords

Have you checked the fluid level?

Follow the advice to check transmission fluid level first.
In park does the engine run rough? If yes then the engine problem might causing the issues with transmission. P0401 is related to egr system. Rest 2 address for pressure and solenoid actuation.

Clear the codes and start the car. Leave it in park. Which codes show up again during park?

P0401-EGR Flow Insufficient (Generic)
P0730-Gear Ratio Incorrect (Generic)
P1751-Shift Solenoid A CKT Performance Or Stuck Off (Manufacturer Specific)

Hope that helps