Technician reported NLG wheel assemblies were missing hubcaps and a discrepancy with the required documentation. The aircraft was removed from service for repair.

Narrative

Aircraft X arrived ZZZ with ETOPS PDSC (Pre-departure Service Check). Noticed both NLG wheels missing hubcaps so began to look at paperwork and found AMM XX-XX-XY requires hubcaps to be installed added per ECRA XXXX-XXXXX. Logpage X was created for missing hubcaps. A further research showed that this ECRA XXXX-XXXXX was issued just 4 months ago on date requiring hub cap installation. Not only that; but this was updated in NLG wheel/tire remove/install AMM XX-XX-XY as a step to remove/install hubcaps. And also added AMM XX-XX-XY specifically for hubcap removal/install.So now there 3 documents showing hubcaps required; but no hubcaps are shown in [the maintenance program]! What a mess. Contacted engineering to clarify this confusing; misleading; conflicting; inadequate paperwork but did not offer resolution right away. Instead engineering suggested to defer per card XXXXXX which will give them more time to sort out; but it was denied by Maintenance based on the fact that hubcaps are not required since there is no TPMS on all B777-200 aircraft... Maintenance did not offer any documentation to justify this. But we have 3 documents showing hubcaps required.