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How to Implement Consent Mode in 2025: A Complete Guide for Google Ads

  • Writer: Flomaticx
    Flomaticx
  • May 27
  • 3 min read

If you run Google Ads or use GA4 to track user behavior, implementing consent mode is no longer optional. With GDPR, ePrivacy, and other privacy regulations tightening across the globe, e-commerce brands and lead-gen marketers need to balance user consent compliance with data-driven performance.

In this guide, we’ll explain what consent mode is, how it works with Google Ads and GA4, and give you a step-by-step walkthrough on how to implement consent mode properly using Google Tag Manager (GTM), a Consent Management Platform (CMP), or custom code.



What Is Google Consent Mode?

Google Consent Mode is a privacy-safe framework that allows your website to adjust how Google tags behave based on your users’ consent choices. Instead of blocking all tags, it tells them what data they're allowed to collect.

Consent mode supports the following types of consent:

  • ad_storage – for advertising cookies like remarketing tags.

  • analytics_storage – for analytics cookies like GA4.

  • functionality_storage, security_storage, and personalization_storage – for additional use cases (introduced in Consent Mode v2).

When a user declines consent, Consent Mode prevents Google from storing cookies but still sends cookieless pings so that you can retain partial measurement (e.g., conversion modeling and attribution reporting).



Why You Need to Implement Consent Mode


For E-commerce Stores:

  • Enables conversion tracking in Google Ads even when users decline cookie usage.

  • Improves data accuracy while staying GDPR-compliant.

  • Helps avoid tag blocking issues caused by cookie banners.

For Lead Generation Sites:

  • Preserves essential data for lead form completions.

  • Ensures remarketing and audience segmentation remain functional where allowed.


Step-by-Step: How to Implement Consent Mode Using GTM


Step 1: Choose a Consent Management Platform (CMP)

Google-certified CMPs like Cookiebot, OneTrust, or Usercentrics make integration much easier. These platforms handle banner display and collect user consent.

Make sure your CMP supports Google’s Consent Mode v2 (mandatory since March 2024 for ad personalization).

Step 2: Load GTM Early in the Page Header

Consent Mode must load before other tags. Add the GTM container snippet in the <head> section to ensure proper sequencing.


<!-- GTM Head Code -->

<script>

(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':

new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],

j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=

'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);

})(window,document,'script','dataLayer','GTM-XXXX');

</script>



Step 4: Integrate With Your CMP

Your CMP should send updates to Google when a user accepts or denies cookies. For example:


gtag('consent', 'update', {

'ad_storage': 'granted',

'analytics_storage': 'granted'

});


Most CMPs offer built-in integrations with GTM and automatically push these consent signals when the user interacts with the cookie banner.

Step 5: Set Consent Checks in GTM

In GTM:

  • Go to each Google tag (GA4, Google Ads Conversion, Remarketing).

  • Under Tag Settings > Consent Settings, enable “Require additional consent”.

  • Confirm tags fire only when the corresponding consent is granted.

Step 6: Test With Google Tag Assistant

Use Google Tag Assistant to verify:

  • Consent is properly detected.

  • Tags are firing (or not) based on consent states.

  • No errors in GA4 or Google Ads tag firing.


After a few days you will see the consent mode implemented:


Screenshot from Google Ads showing conversion tracking status. It indicates that conversions are actively being recorded with the last activity and last conversion both dated May 27, 2025. Enhanced Conversions and Consent Mode are both active, with diagnostic links available.
Consent Mode Implemented and Working Propely


Additional Notes for Consent Mode in 2025


  • Consent Mode v2 is required for ad personalization and audience building in the EEA and UK.

  • Without it, Google Ads remarketing lists won’t work for users in these regions.

  • For YouTube ads, the ad_user_data and ad_personalization fields also need to be defined based on consent.

Example implementation:


gtag('set', 'ads_data_redaction', true);

gtag('consent', 'default', {

'ad_storage': 'denied',

'analytics_storage': 'denied',

'ad_user_data': 'denied',

'ad_personalization': 'denied'

});


FAQs About Implementing Consent Mode


How do I know if my CMP supports Google Consent Mode?Check if your provider is Google-certified for Consent Mode. Most modern platforms include native support.


Can I use Consent Mode without a CMP?Yes, but you’ll need to write your own logic for detecting user consent and pushing updates to gtag()—which is technically advanced and less reliable than using a dedicated CMP.


Does Consent Mode affect conversion tracking?Yes—positively. It allows Google to use modeled conversions when cookies are denied, helping preserve attribution data in GA4 and Google Ads.


Is Consent Mode mandatory?For advertisers using Google Ads in the EU/UK and running personalized ads or remarketing, Consent Mode v2 is required as of March 2024.


Conclusion: Implement Consent Mode to Future-Proof Your Tracking

Implementing consent mode ensures you're compliant with privacy laws without sacrificing key insights from Google Ads and GA4. With evolving regulations and signal loss increasing, consent mode isn’t just a nice-to-have—it's essential for every data-driven marketer.

Need help configuring consent mode on your e-commerce site or lead-gen funnel?

Contact us at Flomaticx – Your Google Ads Performance Partner! We’ll handle the technical setup, consent compliance, and make sure your data stays accurate and actionable.


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