Challenge of an arbitral award for nullity is a limited form of challenge, permitted only for certain procedural defects and for non-observance of legal rules exclusively within the limits of Article 829 of the Code of Civil Procedure. It does not give rise to an appeal judgment that would enable the challenge judge to re-examine the arbitrators' decision on the merits. It allows only what is called the rescissory judgment.
Nullity of an award under Article 829 Nos. 4 and 5 of the Code of Civil Procedure for missing or contradictory reasoning is relevant only when it makes it absolutely impossible to reconstruct the logical and legal thinking underlying the decision because there is a complete absence of reasoning that can be traced to its functional model, or when the reasoning is so inadequate as not to allow reconstruction of the logical path followed by the arbitrators.
Challenge of an arbitral award cannot be brought simply by alleging gaps in investigation and reasoning. Instead, it requires specification of the content of the challenged ruling, the rule allegedly violated, and the specific reasons why the decision must be considered defective, with arguments that are intelligible and exhaustive.