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, advanced implementations send cookieless pings that Google uses to model the missing conversions; basic implementations block the tags entirely. For users in the European Economic Area, the UK and Switzerland, v2 signals are required for remarketing and audience features to keep working.
Why conversions can drop
Deploy Consent Mode without conversion modeling (advanced mode), 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.
Common questions
Is Consent Mode v2 mandatory?
To use European Economic Area user data for Google Ads personalization and remarketing, yes. Without the v2 consent signals, those audiences stop populating.
Why did my conversions drop after enabling Consent Mode?
Usually a configuration issue: consent defaults set wrong, modeling not active, or tags firing before consent is read. The drop is in measurement, not necessarily in real performance.