Plays an essential role in the repair of DNA double-strand breaks by homologous recombination and in the repair of interstrand DNA cross-links (ICLs) by promoting FANCD2 monoubiquitination by FANCL and participating in recruitment to DNA repair sites (PubMed:17412408, PubMed:17460694, PubMed:17452773, PubMed:19111657, PubMed:36385258). The FANCI-FANCD2 complex binds and scans double-stranded DNA (dsDNA) for DNA damage; this complex stalls at DNA junctions between double- stranded DNA and single-stranded DNA (PubMed:19589784). Participates in S phase and G2 phase checkpoint activation upon DNA damage (PubMed:25862789). {ECO:0000250|UniProtKB:B0I564, ECO:0000269|PubMed:17412408, ECO:0000269|PubMed:17452773, ECO:0000269|PubMed:17460694, ECO:0000269|PubMed:19111657, ECO:0000269|PubMed:19589784, ECO:0000269|PubMed:25862789, ECO:0000269|PubMed:36385258}. This is the function of FANCI (FA complementation group I, ENSG00000140525).