Siman 435
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א לֹא בָּדַק בְּלֵיל י"ד, יִבְדֹּק בְּיוֹם י"ד בְּאֵיזוֹ שָׁעָה שֶׁיִּזְכֹּר מֵהַיּוֹם. לֹא בָּדַק כָּל יוֹם י"ד, יִבְדֹּק בְּתוֹךְ הַפֶּסַח. לֹא בָּדַק בְּתוֹךְ הַפֶּסַח, יִבְדֹּק לְאַחַר הַפֶּסַח, כְּדֵי שֶׁלֹּא יִכָּשֵׁל בְּחָמֵץ שֶׁעָבַר עָלָיו הַפֶּסַח שֶׁהוּא אָסוּר בַּהֲנָאָה; וְעַל הַבְּדִיקָה שֶׁלְּאַחַר הַפֶּסַח לֹא יְבָרֵךְ.
1 The law regarding one who did not check on the night of the 14th. Containing 1 paragraphs: If one did not check on the night of the 14th, they should check on the 14th day at whatever time they remember. If they did not check the entire 14th day, they should check during Passover. If they did not check during Passover, they should check after Passover so as not to fail regarding leavened bread that passed over it during Passover, which is forbidden for benefit. And concerning the checking after Passover, one should not recite a blessing.