Consent Mode v2 is Google's framework for adjusting how its tags behave based on a user's consent choices. It adds two signals, ad_user_data and ad_personalization, and is required to use European audience data in Google Ads.
What changed in v2
The original Consent Mode governed ad_storage and analytics_storage. Version 2 added ad_user_data and ad_personalization. When consent is denied, tags send cookieless pings instead of full data, and Google models the missing conversions. For users in the European Economic Area, v2 signals are mandatory for remarketing and audience features to keep working.
Why conversions can drop
Deploy Consent Mode without behavioral modeling, or misconfigure the defaults, and reported conversions can fall sharply, not because performance changed but because measurement did. Setting consent defaults to denied before the tag manager loads, then updating on choice, is the correct order, and getting it wrong is a common cause of a mysterious conversion drop.