No, but they claim to.
They wrongfully understand sola scriptura to mean “no creed but the Bible”—that the Bible is the Church’s only theological resource. This is because they are using their prophetess, Ellen G. Whites, erroneous definition.
Sola scriptura is the belief that the scriptures are the only infallible rule of faith and practice for the Church, the keyword being infallible. Not that they are the only theological resource outright. It has to do with infallible sources and how many the Christian church has. The Protestant Reformers argued the Bible is the only god-breathed source of revelation from God (2 Timothy 3:16-17), not Scripture and the Church. Therefore, the scriptures can be the only infallible source of authority for the Church. Sola scriptura is really a claim regarding the ontological nature of the Bible.
The other reason the Adventist Church doesn’t truly affirm sola scriptura is because they have two other sources of infallible authority.
The first being the writings of Ellen G. White, which they believe are inspired no differently than that of the scriptures. Her writings function as an infallible, interpretive guide to properly understanding the Bible, thus, her writings function over top of the Bible.
The other source being the SDA General Conference when in session. Ellen White claimed to be shown by God that when the General Conference is in session, it is the highest governing authoritative body on earth and that they have the power to make something doctrinally so and “private independence and private judgment must not be maintained, but be surrendered” to them.
Sola scriptura was a foundational battle cry during the Protestant Reformation over and against the idea that both scripture and the Church are infallible which eventually resulted in the Church being premier over and against scripture. The order had become reversed. The Reformers were not advocating for the Church, or even tradition, having zero level of authority, but rather that scripture alone was infallible and supreme.
With this came the belief that scripture was inerrant (which the SDA Church rejects) because of the source by which it came from—God. This is what uniquely distinguishes it from anything else, such as tradition and Church authority. There was also a common belief regarding the perspicuity (clarity) of scripture with the clear passages being what interprets the unclear.
The Reformers claimed to arrive at this conclusion from scripture but also found support from those that came before them who also saw the same thing in scripture, it was not novel to the Reformers. A number of examples include:
Irenaeus of Lyons (130—200 A.D.)
For by the fact that they thus endeavor to explain ambiguous passages of Scripture (ambiguous, however, not as if referring to another god, but as regards the dispensations of [the true] God), they have constructed another god, weaving, as I said before, ropes of sand, and affixing a more important to a less important question. For no question can be solved by means of another which itself awaits solution; nor, in the opinion of those possessed of sense, can an ambiguity be explained by means of another ambiguity, or enigmas by means of another greater enigma, but things of such character receive their solution from those which are manifest, and consistent and clear.ANF: Vol. I, Against Heresies, 2:10:1
If, therefore, according to the rule which I have stated, we leave some questions in the hands of God, we shall both preserve our faith uninjured, and shall continue without danger; and all Scripture, which has been given to us by God, shall be found by us perfectly consistent; and the parables shall harmonize with those passages which are perfectly plain; and those statements the meaning of which is clear, shall serve to explain the parables; and through the many diversified utterances [of Scripture] there shall be heard one harmonious melody in us, praising in hymns that God who created all things. If, for instance, any one asks, “What was God doing before He made the world? ”we reply that the answer to such a question lies with God Himself. For that this world was formed perfect by God, receiving a beginning in time, the Scriptures teach us; but no Scripture reveals to us what God was employed about before this event. The answer therefore to that question remains with God, and it is not proper for us to aim at bringing forward foolish, rash, and blasphemous suppositions [in reply to it]; so, as by one’s imagining that he has discovered the origin of matter, he should in reality set aside God Himself who made all things.ANF: Vol. I, Against Heresies, 2:28:3
Tertullian (160—220 A.D.)
Well, if it occurs occasionally in certain portions of it, you will say, then why not in that phrase, where the resurrection might be spiritually understood? There are several reasons why not. First, what must be the meaning of so many important passages of Holy Scripture, which so obviously attest the resurrection of the body, as to admit not even the appearance of a figurative signification? And, indeed, (since some passages are more obscure than others), it cannot but be right — as we have shown above — that uncertain statements should be determined by certain ones, and obscure ones by such as are clear and plain; else there is fear that, in the conflict of certainties and uncertainties, of explicitness and obscurity, faith may be shattered, truth endangered, and the Divine Being Himself be branded as inconstant.ANF: Vol. III, On the Resurrection of the Flesh, Chapter 21
John Chrysostom (347—407 A.D.)
He [John the Apostle} did not hide his teaching in mist and darkness, as they did who through obscurity of speak, like a kind of veil, around the mischiefs laid up within. But this man’s [John’s] doctrines are clearer than the sunbeams, wherefore they have been unfolded to all men throughout the world. For he did not teach as Pythagoras did, commanding those who came to him to be silent for five years, or to sit like senseless stones; neither did he invent fables defining the universe to consist of numbers; but casting away all this devilish trash and mischief, he [John] diffused such simplicity through his words, that all he said was plain, not only to wise men, but also to women and youths. For he was persuaded that the words were true and profitable for all that should harken them.Homilies 2 on the Gospel of John
“For we which live are also delivered unto death for Jesus’ sake, that the life also of Jesus may be manifested in us in our mortal flesh.” For every where when he has said any thing obscure, he interprets himself again. So he has done here also, giving a clear interpretation of this which I have cited. ‘For therefore, “we are delivered,”’ he says, ‘in other words, we bear about His dying that the power of His life may be made manifest, who permitteth not mortal flesh, though undergoing so great sufferings, to be overcome by the snowstorm of these calamities.’ And it may be taken too in another way. How? As he says in another place, “If we die with him, we shall also live with Him.” (2 Timothy 2:11) ‘For as we endure His dying now, and choose whilst living to die for His sake: so also will he choose, when we are dead, to beget us then unto life. For if we from life come into death, He also will from death lead us by the hand into life.’Homilies 9 on 2 Corinthians
Anyhow, in case by wanting to make a display of these people’s stupidity we, too, find ourselves induced to utter unseemly remarks, let’s have done with their folly and turn aside from such idiocy; let us follow the direction of Sacred Scripture in the interpretation it gives of itself, provided we don’t get completely absorbed with the concreteness of the words, but realize that our limitations are the reason for the concreteness of the language. Human senses, you see, would never be able to grasp what is said if they had not the benefit of such great considerateness.Fathers of the Church, Vol. 74, Homilies on Genesis 1-17, 13.8
Basil of Caesarea (330—379 A.D.)
What seems to be said in an ambiguous and veiled way in certain passages of inspired Scripture is made plain by the obvious meaning of other passages.W. K. L. Clarke, The Ascetic Works of Saint Basil, Translations of Christian Literature Series I, Greek Texts (London: S.P.C.K., 1925), The Shorter Rules, Answer #267 (CCLXVII), p. 329
You could find many passages of this sort in the writings of the evangelists and the Apostle. Now, then, if a command be given and the manner of carrying it out is not added, let us obey the Lord, who says: ‘Search the Scriptures.’ Let us follow the example of the Apostles who questioned the Lord Himself as to the interpretation of His words, and learn the true and salutary course from His words in another place.Fathers of the Church, Vol. 9, Ascetical Works, On Baptism, Book 2, §3 (New York: Fathers of the Church, Inc., 1950), p. 399
Ambrose (339—397 A.D.)
In most places Paul so explains his meaning by his own words, that he who discourses on them can find nothing to add of his own; and if he wishes to say anything, must rather perform the office of a grammarian than a discourser.Fathers of the Church, Vol. 26, Saint Ambrose: Letters 54. Ambrose to Simplicianus
Jerome (347—420 A.D.)
…let us call upon the Lord, probe the depths of His sacred writings, and be guided in our interpretation by other testimonies from Holy Writ. Whatever we cannot fathom in the deep recesses of the Old Testament, we shall penetrate and explain from the depth of the New Testament in the roar of God’s cataracts—His prophets and apostles.Fathers of the Church, Vol. 57, The Homilies of St. Jerome: Vol. 2, Homily 92
Augustine (354—430 A.D.)
Accordingly the Holy Spirit has, with admirable wisdom and care for our welfare, so arranged the Holy Scriptures as by the plainer passages to satisfy our hunger, and by the more obscure to stimulate our appetite. For almost nothing is dug out of those obscure passages which may not be found set forth in the plainest language elsewhere.NPNF1: Vol. II, On Christian Doctrine, Book II, Chapter 6, §8
What those who fear God and have a docile piety are looking for in all these books is the will of God. The first step in this laborious search, as I have said, is to know these books, and even if not yet so as to understand them, all the same by reading them to commit them to memory, or at least not to be totally unfamiliar with them. Next, those things that are put clearly in them, whether precepts about how to live or rules about what to believe, are to be studied with the utmost care and diligence; the greater your intellectual capacity, the more of these you will find. The fact is, after all, that in the passages that are put plainly in scripture is to be found everything that touches upon faith, and good morals, that is to say hope, charity, which we dealt with in the previous book.
Only then, however, after acquiring some familiarity with the actual style of the divine scriptures, should one proceed to try to open and unravel their obscurities, in such a way that instances from the plainer passages are used to cast light on the more obscure utterances, and the testimony of some undoubted judgments is used to remove uncertainties from those that are more doubtful. In this matter what is of the greatest value is a good memory; if this is wanting, these instructions cannot be of any great assistance.De Doctrina Christiana, Book II, Chapter 9, §14
Cassiodorus (485—585 A.D.)
Happy indeed is the mind that has stored such a mysterious treasure in the depths of memory, with God’s help; but much happier the mind that knows the ways of understanding from its energetic investigation. As a result, such a mind vigorously expels human thoughts and is occupied to its salvation with divine utterances. I recall that I have seen many men with powerful memories who, asked about the most obscure passages, have solved the questions put to them by examples drawn only from divine authority, for a matter stated obscurely in one place is set down more clearly in another book. An example of this is the Apostle Paul who to a large extent in the letter written to the Hebrews elucidates the writings of the Old Testament by their fulfillment in the new times.Cassiodorus, Institutions of Divine and Secular Learning On the Soul, Translated Texts for Historians, Vol. 42, Book 1, Preface, §2, p. 106
The Christian church has always upheld the supremacy and sole infallibility of the sacred scriptures over and against any sort of extra-biblical infallible interpreter—whether that be the Pope or Ellen G. White. The SDA Church has simply replaced the Roman Catholic magisterial authority over scripture with that of the writings of Ellen G. White.
This is a classic case of the Seventh-Day Adventist Church borrowing Protestant terminology to appear like just another Protestant denomination when they are not.