Accidentally put I could be claimed in 2018.

[Jordanrehn]

I said on my taxes in 2018 i could be claimed as a dependent. I was not claimed. 

How can fix this and get a stimulus check?

[SusanY1]

You should amend the return by filing Form 1040X if you were not eligible to be claimed as a dependent.  To do this in TurboTax, log back into your account at TurboTax.com and navigate to Your tax return & documents then select the option "Amend(change) return" and follow the prompts.

Amended returns are filed by mail and typically take 8-12 weeks to process.  Processing times right now are significantly delayed due to reductions in staff.

It is not known if, upon processing, an advance payment will be sent.

Any taxpayer whose advance payment received is less than the full payment for which he or she is entitled, will be eligible to claim the difference as a credit on the 2020 tax return filed in 2021.

Please check these links frequently for updates:

IRS Economic Impact Payment

TurboTax Coronavirus Updates