Checking and understanding Consent Mode v2 in GA4
With Consent Mode v2, Google introduced two new signals: ad_user_data
and ad_personalization. Anyone who sets neither or sets them wrong risks
audiences, remarketing and conversion modelling silently failing -
without any error message. The GA4 Auditor checks exactly that
automatically. This page shows you what matters and how to check your
Consent Mode v2 yourself in minutes.
What Consent Mode v2 is
Consent Mode v2 is an interface through which you tell Google the consent
status of your visitors. Before v2, ad_storage and analytics_storage
were enough. The two new signals now explicitly control whether a user may
be included in personalisation and modelling. If a user declines, Consent
Mode sends anonymised pings from which Google models missed conversions.
How to check Consent Mode v2
Three routes, from the fastest to the most thorough:
- GA4 Auditor (on-page check) - the headless browser scans your page
in the phase before and after the consent decision, detects 14 CMPs and
reads the default and updated consent state directly from the
dataLayer. - GTM preview mode - check whether your tags are set to
deniedwhile the banner has not yet been accepted and switch tograntedafter "Accept". - GA4 diagnostics - under Admin > Diagnostics, a green status confirms the active consent mode.
The six consent signals
| Signal | Controls | Relevant for |
|---|---|---|
ad_storage |
advertising cookies | Google Ads |
analytics_storage |
analytics cookies | GA4 |
functionality_storage |
functional data (e.g. language) | website |
personalization_storage |
personalised content | website |
ad_user_data (new) |
sharing user data with Google | Ads, Enhanced Conversions |
ad_personalization (new) |
personalised advertising / remarketing | Ads |
How to set it correctly
- Set the default values BEFORE every
gtag('config', ...). - Update them immediately after the CMP decision - without a page reload.
- Validate in the auditor's tracking debugger whether both new signals are actually sent.
Common mistakes
- The default consent is set too late, tags already fire on
granted. ad_user_dataandad_personalizationare missing entirely - the v1 setup was never extended to v2.- The CMP only updates the state after a reload instead of immediately.
Related topics
- Understanding Consent Mode v2 (help) - step by step in the app.
- Data security in the GA4 Auditor - why we work read-only and EU-hosted.
- GA4 audit checklist - all checks at a glance, including the consent check.
Frequently asked questions
- How do I check whether Consent Mode v2 works?
- The fastest way is via three routes: The GA4 Auditor's on-page check scans your page before and after the consent decision and shows the default and updated consent state. In GTM preview mode you can see whether tags are set to 'denied' before consent and switch to 'granted' after the click. In GA4 under Admin > Diagnostics, a green status confirms the active consent mode.
- Which signals belong to Consent Mode v2?
- Consent Mode v2 uses six signals: ad_storage, analytics_storage, functionality_storage, personalization_storage as well as the two signals new with v2, ad_user_data (sharing user data with Google) and ad_personalization (personalised advertising/remarketing). For GA4 analytics_storage is relevant; for Google Ads ad_user_data and ad_personalization are additionally relevant.
- Is Consent Mode v2 mandatory?
- For advertisers using Google Ads remarketing or audiences in the EEA, Consent Mode v2 has effectively been mandatory since March 2024: without correctly set ad_user_data and ad_personalization signals, Google stops personalisation and conversion modelling. Plain GA4 measurement also works without it, but loses the modelling of declined sessions.
- What does ad_user_data mean?
- ad_user_data controls whether personal data may be sent to Google for advertising purposes - for example for Enhanced Conversions. If it is set to 'denied', Google prevents the sharing. The GA4 Auditor checks whether the signal is set at all and whether it correctly switches to 'granted' after the CMP decision.