TurboTax can't directly handle calculating the maximum permissible solo 401(k) contribution when you also made employee contributions to another employer's plan.  Since you contributed $17,000 to the other employers plan and you can only contribute $7,500 in elective deferrals and Roth contributions to the solo 401(k), enter you elective deferral or Roth contribution explicitly, limiting the total to $7,500.  For the employer contribution, you can get TurboTax to calculate the maximum permissible employer contribution by marking the Maximize box for either a Profit Sharing Keogh or a SEP contribution; the calculation is the same.