Here is a post where I explained paticca samuppada
In addition to viññāna being “corrupt consciousness”, it is also important to realize that ALL the terms in the akusala-mula paticca samuppada (Dependent Origination) are corrupt or bad. That is why one ends up with suffering. This akusala-mula PS, starts with avijja (ignorance) and ends up in dukkha, domanassa, etc (suffering).
Viññāna means “without ñāna ” or without wisdom: in very simple terms, not knowing the consequences of doing dasa akusala.
Let us go through the PS process involved in person X making plans to kill Y to marry his wife. Person X’s goal is to marry Y’s wife and live a happy life with her. And X does not understand that it will lead to bad consequences for him in the future, i.e., bring a birth in the apayas (one of the four lowest reals, most likely the lowest realm, niraya).
Therefore, X thinks, speaks, and acts unwisely (doing mano, vaci, and kaya sankhara, which are actually abhisankhara). That is the “avijja paccaya sankhara” step.
That leads to the defiled consciousness, where X constantly thinks about his goal, which leads to a defiled state of mind, i.e., “sankhara paccaya viññāna”.
Concurrently, X is visualizing not only how he will live a happy life with that lady, but also how he will carry out the plan to kill Y. These visualizations are the namarupa that X generates in his mind. This is the “viññāna paccaya namarupa” step.
Here, X will be constantly making abhisankhara too. So, these three steps go back and forth numerous times, making more abhisankhara and namarupa, thus strengthening viññāna.
For example, in addition to “viññāna paccaya namarupa” step, there will be “namarupa paccaya viññāna” step and the same for others.
This leads to the arising of a potent kamma bija via javana citta that run constantly through X’s mind. That is what brings a bad birth in the future. Now, suppose X kills Y. Now the kamma or the “bad deed” is complete (which is called a kamma patha), and a potent kamma bija (kammic energy) or a “seed” has been created which can last many aeons waiting for an opportunity to bring a bad birth for X.
So, the rest of the PS cycle starts when a new bhava is about to be grasped by X, which could be at the end of this human bhava or even millions of years later.
Anyway, when that happens, the PS cycle will go through the second half starting with “viññāna paccaya namarupa” step. That kamma bija which was created some time back, will now come to his mind and will flash a namarupa (or a nimitta or a sign) compatible with the new bhava.
That nimitta will come through one of the six sense faculties (salayatana), which is the next step in PS: “namarupa paccaya salayatana”.
Now, X’s mind will make contact with that nimitta: “salayatana paccaya phasso”, which will lead to “phassa paccaya vedana”, i.e., X will experience that nimitta or namarupa of the new bhava that he is about to grasp.
For example, it could be a scene from the niraya (hell) that X is going to be born in. This is why some people either cry of in fear or show that fear in their eyes at the moment of death.
Then his mind will grasp it, “vedana paccaya tanha”, and will embrace it: “tanha paccaya upadana”, which means X has now grasped that new bhava: “upadana paccaya bhavo”.
Then, X will be born in that bhava (existence), which in this case is an existence in the niraya, and instantaneously be born in that bhava: “bhava paccaya jati”.
That is how the suffering in that next existence starts, and X will now undergo suffering until that kammic energy (or the bhava energy) is exhausted. At the end of that, X will again come to a cuti-patisandhi moment and will grasp a new bhava that will be based on another good or bad kamma bija that was created in the past. This is how the rebirth process continues.
That is a highly condensed version of a PS cycle, which is called uppatti PS, because that is responsible for leading to a birth in a new bhava (existence).
I would be happy to discuss details, if any of the above is not clear. If one can go back and read my earlier posts in this thread and other thread on “The Teachings of Waharaka Abhayaratanalankara Thero”, that could also be helpful to fill in gaps.
Some people think “namarupa” means what one sees, hears, etc. But that process of seeing or hearing happens in a billionth of a second in a single citta vithi with 17 thought moments. It should be noted that “namarupa formation” is a very deep subject. It is the viññāna that combines nama and rupa and gives rise to namarupa. This understanding is called “namarupa paricceda ñāna”.
By the way, “viññāṇāṁ anidassanaṁ anantaṁ sabbato pabhaṁ” means “Viññāna is unseen, infinite, and leads to the rebirth process for all”. This is discussed in detail at, “https://puredhamma.net/living-dhamma/na