Consent Mode is a Google mechanism that adjusts how Google tags, such as GA4 and Google Ads, behave according to the visitor’s consent choices. The consent management platform (CMP) passes on the state of each category and the tags adapt to it.
Version 2 uses four main parameters: ad_storage and analytics_storage, which control cookie storage for advertising and analytics, and ad_user_data and ad_personalization, which indicate whether user data may be sent to Google for advertising purposes and for ad personalisation.
There are two ways to implement it. In basic mode, Google tags only load after the visitor consents. In advanced mode, tags load with consent denied by default and send cookieless signals that Google can use to model conversions. Which one to use should be weighed up with whoever advises the store on privacy.
Consent Mode does not replace the CMP or consent itself: it simply relays the visitor’s decision to the tags. If the CMP is misconfigured, Consent Mode will be too.