No, TurboTax has not been programmed with the ability to do this. If you make employee contributions to a different employer's plan, you cannot use the Maximize function for a solo 401(k) contribution. You'll have to manually calculate and enter the amount of your employee contribution to the solo 401(k), but you can use the Maximize function for a SEP IRA contribution to calculate the maximum permissible employer contribution to the solo 401(k).
