We had problems with our 03 because I used aftermarket transmission fluid. It caused the 1st and 2nd gears to slip, caused solenoid to malfunction making the D light blink, made the Check Engine and TCS light to come on. Took it to dealer charge me 95.00 to tell me it had P1040? trouble code and I needed to replace it transmission at 6,000. We barely had over 100,000 miles.
I bought new solenoid online for 43.00, changed the fluid 3 times with genuine Honda ATF-Z1 fluid, at 3.8 quarts per change and unplugged the + cable to battery for 15 min. to reset any troublecodes in computer memory.
So far its worked, no more trouble lights and no slipping in any gear. IF YOU CAN, DO NOT BE SUCKERED INTO BUYING OR REBUILDING YOUR TRANSMISSION, IT WILL ONLY FAIL AGAIN AND AGAIN.