Google Consent Mode v2: What It Is and How to Implement It

The short answer

Consent Mode is an API in gtag.js and Google Tag Manager that passes the visitor's consent state to Google Ads and GA4 tags. It does not ask the visitor anything itself: your cookie banner collects consent, and Consent Mode delivers the result to the tags.

Version 2 added two signals to the existing ones. The full set for ads and analytics:

Each signal is either granted or denied.

How it works technically

The logic is always the same: a default state first, then an update.

1. Before any tag loads, you set a default, usually everything denied in regions that require consent.
2. The visitor makes a choice in the banner.
3. The banner calls update with the new values.

<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('consent', 'default', {
    ad_storage: 'denied',
    analytics_storage: 'denied',
    ad_user_data: 'denied',
    ad_personalization: 'denied',
    wait_for_update: 500
  });
</script>

When the visitor clicks "Accept", the banner calls gtag('consent', 'update', {...}) with granted for the allowed categories. wait_for_update gives the banner time (in milliseconds) to load before the first hits go out. The region parameter lets you set different defaults per country.

Basic vs advanced mode

Basic mode is the conservative option: until consent, Google receives nothing. Advanced mode sends anonymous signals (that an event happened, no cookies), which gives Google more material for modeling. The choice is as much your privacy lawyer's call as a technical one.

Conversion modeling

When a visitor declines cookies, a click on an ad cannot be directly linked to a purchase. Google fills the gap with modeling: it uses the behavior of consenting users to estimate how many conversions came from those who declined.

What to keep in mind:

• Modeled conversions appear in Google Ads reports next to observed ones and feed automated bidding.
• GA4 has separate behavioral modeling, but it only switches on above certain traffic and daily event thresholds, so a small site may not get it.
• A model is an estimate, not a fact. Check trends against your CRM.

When Consent Mode is required

Since 2024, Google requires consent signals if you use advertising features (remarketing, personalization, conversion measurement) for users in the European Economic Area, as well as the UK and Switzerland. Without ad_user_data and ad_personalization, audiences and measurement for that traffic degrade.

If your audience is only in Uzbekistan or the CIS, Google's requirement does not formally apply. But if a noticeable share of traffic comes from the EU, or you plan to advertise there, implement it now. Also check local personal data law: Consent Mode does not replace compliance with it.

Banner integration, step by step

1. Pick a CMP (consent management platform) that supports Consent Mode v2. For AdSense, Ad Manager and AdMob in the EEA, Google requires a certified CMP.
2. Connect it via GTM: most CMPs ship a tag template. Fire it on the Consent Initialization – All Pages trigger so the default runs before every other tag.
3. Enable consent overview in the GTM container settings and review which Google tags have built-in consent checks and which third-party tags need checks added manually.
4. Set regions: strict defaults for the EEA, looser ones elsewhere if your policy allows it.
5. Optionally enable url_passthrough (passes click parameters in URLs without cookies) and ads_data_redaction (drops ad identifiers when consent is denied).

How to verify the setup

• In Tag Assistant, open the Consent tab to see the default and updated states.
• In DevTools, the Network tab shows gcs and gcd parameters on Google requests; they encode the consent state.
• Google Ads conversion diagnostics show the Consent Mode status.

Common mistakes:

• The default fires after the first tags, so early hits go out with no status.
• The banner updates only ad_storage and analytics_storage and forgets the two new signals.
• Meta, TikTok and other tags keep running without consent: Consent Mode only governs Google tags.