What is Consent Mode v2 and how to configure it?

Consent Mode v2 is a Google mechanism that adapts the behavior of Google tags (Analytics, Ads, Floodlight) based on user consent. In practice, Google tags fire in all cases but modify their behavior according to consent status: with consent, they function normally; without consent, they send cookieless pings without personal identifiers.

Version 2, mandatory since March 2024 for advertisers using Google Ads in the EEA, introduces two new parameters: ad_user_data (authorization to send user data to Google for advertising purposes) and ad_personalization (authorization for advertising personalization). These are added to the existing parameters: analytics_storage and ad_storage.

Technical configuration via GTM

Implementation goes through your CMP (Cookiebot, Axeptio, Didomi, etc.) coupled with Google Tag Manager. The CMP must communicate user choices to GTM via the gtag(‘consent’, ‘update’, {…}) command. In GTM, enable built-in consent settings on each Google tag, or configure a default state via a consent tag initialized on page load.

The recommended default state for EEA visitors is to deny all storage types (denied), then update them (granted) after acceptance. Verify proper transmission via the Consent tab in GTM’s Preview mode.

Impact on GA4 data

Without consent, GA4 receives anonymized pings. Google then uses behavioral modeling to estimate the missing data. This modeling requires a minimum volume of consented traffic (approximately 1,000 events per day for 7 days). Modeled data appears in standard reports but is not exported to BigQuery. Enable Consent Mode from the start to maximize the quality of this modeling.

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