Google Consent Mode v2 is an updated version of the user consent management mechanism that became mandatory for advertisers in the European Economic Area (EEA) from March 2024. Without proper implementation, you lose conversion data and remarketing capabilities in Google Ads.

Consent Mode is a Google API that allows you to adjust the behavior of Google tags (Analytics, Ads, Floodlight) based on user cookie consent. Instead of completely blocking tags when a user denies consent, Consent Mode sends “cookieless pings” that enable conversion modeling.

Difference Between v1 and v2

FeatureConsent Mode v1Consent Mode v2
Consent parameters2 (analytics_storage, ad_storage)4+ (added ad_user_data, ad_personalization)
Legal requirementsGDPRGDPR + Digital Markets Act (DMA)
Mandatory from-March 2024 (EEA)
Impact on remarketingPartialFull - no consent, no remarketing

Required Parameters

gtag('consent', 'default', {
  'ad_storage': 'denied',           // Advertising cookies
  'ad_user_data': 'denied',         // Sending user data to Google Ads
  'ad_personalization': 'denied',   // Ad personalization (remarketing)
  'analytics_storage': 'denied',    // Analytics cookies (GA4)
  'wait_for_update': 500            // Wait time for CMP (ms)
});

Parameter Descriptions

ParameterDescriptionTag Impact
ad_storageStorage of advertising cookiesGoogle Ads conversion tracking
ad_user_dataSending user data to GoogleCustomer Match, Enhanced Conversions
ad_personalizationAd personalizationRemarketing, similar audiences
analytics_storageStorage of analytics cookiesGA4 cookies (_ga, _gid)

Optional Parameters

gtag('consent', 'default', {
  // ... required parameters
  'functionality_storage': 'denied',    // Functional cookies (preferences)
  'personalization_storage': 'denied',  // Content personalization
  'security_storage': 'granted'         // Security (always granted)
});

Implementation Modes

Basic Mode

In basic mode, Google tags are not loaded until the user gives consent. This is the simplest implementation, but you lose conversion modeling capability.

// Tags loaded only after consent
if (userConsented) {
  // Load gtag.js
}

Advanced Mode - RECOMMENDED

In advanced mode, tags are always loaded, but their behavior adjusts to consent. When consent is denied, “cookieless pings” are sent - anonymous data without user identifiers.

// Tags always loaded, behavior depends on consent
gtag('consent', 'default', {
  'ad_storage': 'denied',
  'ad_user_data': 'denied',
  'ad_personalization': 'denied',
  'analytics_storage': 'denied'
});

// Later, after consent is given
gtag('consent', 'update', {
  'ad_storage': 'granted',
  'ad_user_data': 'granted',
  'ad_personalization': 'granted',
  'analytics_storage': 'granted'
});

Implementation in Google Tag Manager

  1. Open GTM container
  2. Go to Admin → Container Settings
  3. Check Enable consent overview

Create a Consent Initialization - All Pages tag (type: Custom HTML) with highest priority:

<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}

  // Default settings - everything blocked
  gtag('consent', 'default', {
    'ad_storage': 'denied',
    'ad_user_data': 'denied',
    'ad_personalization': 'denied',
    'analytics_storage': 'denied',
    'functionality_storage': 'denied',
    'personalization_storage': 'denied',
    'security_storage': 'granted',
    'wait_for_update': 500
  });

  // Region-specific defaults (optional)
  gtag('consent', 'default', {
    'ad_storage': 'granted',
    'ad_user_data': 'granted',
    'ad_personalization': 'granted',
    'analytics_storage': 'granted',
    'region': ['US', 'CA'] // Outside EEA - default granted
  });
</script>

Trigger: Consent Initialization - All Pages

For GA4 and Google Ads tags:

  1. Open tag (e.g., GA4 Configuration)
  2. Go to Advanced Settings → Consent Settings
  3. Choose:
    • No additional consent required - tag fires always
    • Require additional consent for tag to fire - select required consents

Popular CMP platforms with built-in GTM integration:

  • Cookiebot
  • OneTrust
  • Usercentrics
  • Osano
  • Cookie Information

Example: Cookiebot Integration

<!-- Cookiebot banner script (before GTM) -->
<script
  id="Cookiebot"
  src="https://consent.cookiebot.com/uc.js"
  data-cbid="YOUR-COOKIEBOT-ID"
  data-blockingmode="auto"
  type="text/javascript"
></script>

GTM will receive automatic consent updates through dataLayer.

Example: Custom CMP

If you have your own consent system, send updates to dataLayer:

// After clicking "Accept All"
function acceptAllCookies() {
  gtag('consent', 'update', {
    'ad_storage': 'granted',
    'ad_user_data': 'granted',
    'ad_personalization': 'granted',
    'analytics_storage': 'granted'
  });

  // Save choice in localStorage/cookie
  localStorage.setItem('cookie_consent', JSON.stringify({
    ad_storage: true,
    ad_user_data: true,
    ad_personalization: true,
    analytics_storage: true,
    timestamp: Date.now()
  }));
}

// After clicking "Essential Only"
function acceptEssentialOnly() {
  gtag('consent', 'update', {
    'ad_storage': 'denied',
    'ad_user_data': 'denied',
    'ad_personalization': 'denied',
    'analytics_storage': 'denied'
  });

  localStorage.setItem('cookie_consent', JSON.stringify({
    ad_storage: false,
    ad_user_data: false,
    ad_personalization: false,
    analytics_storage: false,
    timestamp: Date.now()
  }));
}

Step 5: Read Saved Consents on Return

// At the start of each session
(function() {
  const savedConsent = localStorage.getItem('cookie_consent');
  if (savedConsent) {
    const consent = JSON.parse(savedConsent);
    gtag('consent', 'update', {
      'ad_storage': consent.ad_storage ? 'granted' : 'denied',
      'ad_user_data': consent.ad_user_data ? 'granted' : 'denied',
      'ad_personalization': consent.ad_personalization ? 'granted' : 'denied',
      'analytics_storage': consent.analytics_storage ? 'granted' : 'denied'
    });
  }
})();

Impact on GA4 and Google Ads Data

Full tracking as before:

  • Cookies _ga, _gid set normally
  • Full demographic and interest data
  • Remarketing works
  • Enhanced Conversions active

Google applies Conversion Modeling and Behavioral Modeling:

  • Cookieless pings - anonymous data without identifiers
  • Conversion modeling - Google estimates missing conversions based on patterns
  • No remarketing - user won’t be in audience lists
  • No cross-device tracking - sessions won’t be linked

Requirements for Conversion Modeling

For modeling to work properly, you need:

  1. Minimum data - sufficient traffic with consents
  2. Advanced Mode - Basic Mode doesn’t support modeling
  3. Google signals - enabled in GA4
  4. Linking - GA4 connected to Google Ads

Verifying Implementation

GTM Preview Mode

  1. Open GTM Preview
  2. Check the Consent tab
  3. Ensure that:
    • Default values are denied
    • After banner interaction, values update
    • Tags react to consent changes

Chrome DevTools

// Check current consent state
console.log(google_tag_data.ics.entries);

// Or
dataLayer.filter(item => item[0] === 'consent');

Google Tag Assistant

  1. Install the Google Tag Assistant extension
  2. Check if tags report correct consent states
  3. Look for Consent Mode error messages

GA4 DebugView

  1. Open GA4 → Configure → DebugView
  2. Look for gcs (Google Consent State) parameter in events
  3. Values:
    • G100 = all consents granted
    • G110 = ad_storage denied, analytics granted
    • G111 = only analytics denied

Common Problems and Solutions

Cause: Cookie banner doesn’t send gtag('consent', 'update', ...).

Solution: Check CMP integration or add your own calls.

Problem: Tags Fire Before Banner

Cause: Missing wait_for_update or timeout too short.

Solution:

gtag('consent', 'default', {
  // ...
  'wait_for_update': 2000 // Increase timeout
});

Problem: No Conversion Modeling

Cause: Basic Mode or insufficient data.

Solution: Switch to Advanced Mode and wait for sufficient data (minimum several hundred conversions with consent).

Problem: Remarketing Doesn’t Work

Cause: ad_personalization: 'denied'.

Solution: This is legally compliant - user denied remarketing consent. Focus on First-Party Data strategies.

GDPR and DMA Compliance

  1. Explicit consent - checkbox must be unchecked by default
  2. Easy withdrawal - user must be able to easily change their mind
  3. Equal options - “Accept” and “Reject” equally visible
  4. Information - clear description of what cookies do
  5. Documentation - record consents as proof

Digital Markets Act (DMA)

From March 2024, DMA requires:

  • Explicit consent for ad_user_data and ad_personalization
  • Without these consents, Google Ads remarketing is impossible
  • Enhanced Conversions require ad_user_data: 'granted'

Summary

Google Consent Mode v2 is an essential element of every website operating in the EEA. Key points:

  1. Mandatory implementation from March 2024 for advertisers in EEA
  2. Advanced Mode allows conversion modeling when consent is denied
  3. Four parameters - ad_storage, ad_user_data, ad_personalization, analytics_storage
  4. CMP integration - use a certified platform for easy implementation
  5. Testing - GTM Preview, Tag Assistant, GA4 DebugView

Proper implementation protects against loss of conversion data and ensures compliance with GDPR and Digital Markets Act.

Sources

  1. Google Developers - Consent mode https://developers.google.com/tag-platform/security/guides/consent

  2. Google Ads Help - Consent mode implementation https://support.google.com/google-ads/answer/10000067

  3. Google Analytics Help - Consent mode for websites https://support.google.com/analytics/answer/9976101

  4. Google - EU user consent policy https://www.google.com/about/company/user-consent-policy/

  5. Google Tag Manager - Consent overview https://support.google.com/tagmanager/answer/10718549

  6. European Commission - Digital Markets Act https://digital-markets-act.ec.europa.eu/