how many solenoid valve how much are solenoid for 2000 Honda Accord Lx 2.3 liter and can you put them on by yourself.

Anymore info would be great. There are only 50 things called solenoids on cars. So I'd say from 20 to 1000 bucks could be a safe guess

what solenoid valve???

trans ? Waste of time and money regardless of what code and parts store tells you. Solenoid codes pop up after the other internal failures that cause them are beyond repair.