How to check that Consent Mode v2 works
Having a cookie banner does not mean Consent Mode v2 is sending the right signals to Google. You can check it in 5 minutes with your browser and Google's official tool, with nothing to install. This guide shows what to look at, which values are correct and which mistakes come up most.
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What you should see before and after accepting
Google Analytics requests include the gcs parameter, which summarises the consent state: G100 means ads and analytics denied, G111 means both granted. The gcd parameter also carries the state of the four version 2 signals, including ad_user_data and ad_personalization. If gcd is missing from every request, your site is not sending full Consent Mode v2.
Check the default state from the console
In the browser console type dataLayer.filter(e => e[0] === 'consent') and review the entries. The first must be 'default' with the four signals (ad_storage, analytics_storage, ad_user_data, ad_personalization) set to 'denied' for EU visitors, and it must appear before any gtag or GTM configuration. After accepting, an 'update' entry with 'granted' values must appear.
The 5 most common mistakes
- The default state is declared after loading gtag.js or the GTM container, so the first requests go out unrestricted.
- Only ad_storage and analytics_storage are sent (version 1): ad_user_data and ad_personalization are missing, and Google Ads stops using your EU audiences.
- The banner shows the notice but analytics or Meta Pixel scripts have already run: _ga or _fbp cookies exist before accepting.
- GTM tags have no consent checks, so they fire even if the user rejects.
- Rejecting reverts nothing: after pressing “Reject all” the state stays 'granted' because of an old consent cookie.
If something does not add up
The most common cause is ordering: the default state must load first and every other script must stay blocked until consent. With Consentio the snippet declares the four signals as 'denied' before anything else and blocks scripts until the visitor accepts, so if you use another CMP the test above shows exactly where it differs.
Want a setup that already sends the four signals and blocks scripts before consent? Create your free account at /registro or compare plans at /precios.
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This guide is informational and not legal advice.