[Backwardsman97]

You have one too many closing brackets.

pawn Код:

dcmd_tune(playerid, params[])
{
    #pragma unused params

    if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
        return ModCar(playerid);
    else
        return SendClientMessage(playerid, COLOR_RED, "You Must Be Inside & Driver Of Vehicle To Tune!");
}

At least from the code you gave.