As Google enforces Consent Mode v2, marketers must not only collect consent—but also route tracking events dynamically based on whether consent has been granted.

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🧰 Prerequisites

Tool/Tech	Requirement
OpenCart v3.x/v4.x	With editable theme files
Google Tag Manager (Web)	Installed properly
GA4 Tag in GTM	Configured with Consent Mode v2
Cookiebot / OneTrust	Cookie consent tool that sets gtag() correctly

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🎯 Goal

✅ Read GA4 consent signals (analytics_storage, ad_storage, etc.)
✅ Conditionally fire GA4, Google Ads, Meta Pixel, TikTok, etc.
✅ Avoid firing events when user has not granted consent
✅ Centralize platform routing based on real consent status

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🔧 Step 1: Enable Google Consent Mode v2

A. Add a Consent Initialization Tag in GTM

• Tag Type: Consent Initialization – Configuration
• Trigger: Consent Initialization – All Pages
• Settings:

ad_storage: denied
analytics_storage: denied
personalization_storage: denied
functionality_storage: granted
security_storage: granted

This prevents all Google tags from firing until consent is updated.

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🔁 Step 2: Sync Cookie Consent with Google Consent Mode

A. Create a Custom HTML tag in GTM

<script>
window.addEventListener('CookieConsentDeclaration', function () {
  gtag('consent', 'update', {
    ad_storage: Cookiebot.consents.marketing ? 'granted' : 'denied',
    analytics_storage: Cookiebot.consents.statistics ? 'granted' : 'denied',
    personalization_storage: Cookiebot.consents.preferences ? 'granted' : 'denied',
    security_storage: 'granted'
  });
});
</script>

• Trigger: Consent Initialization – All Pages

🧠 Adjust this if you use OneTrust, Axeptio, or another tool instead.

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📦 Step 3: Create a Custom JavaScript Variable to Read Consent State

Variable: JS - Consent Analytics

function() {
  try {
    return gtag && gtag.get('consent', 'default')?.analytics_storage || 'denied';
  } catch (e) {
    return 'denied';
  }
}

Variable: JS - Consent Ads

function() {
  try {
    return gtag && gtag.get('consent', 'default')?.ad_storage || 'denied';
  } catch (e) {
    return 'denied';
  }
}

These read the live consent signal pushed by Google Consent Mode.

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🧠 Step 4: Route Events Based on Consent in GTM Tags

Let’s use these variables to control which tags fire and when.

A. GA4 Tag

• Enable Built-in Consent Checks
• Consent type: analytics_storage
• Add trigger condition:JS - Consent Analytics equals granted

B. Google Ads Tag

• Consent type: ad_storage
• Trigger condition:JS - Consent Ads equals granted

C. Meta Pixel Tag (Custom HTML)

Use a Custom HTML Tag that fires only if marketing consent is true:

<script>
fbq('init', 'PIXEL_ID');
fbq('track', 'PageView');
</script>

Trigger: Custom Event CookieConsentDeclaration
Condition:

Cookiebot.consents.marketing equals true

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🔁 Step 5: Shared Event Dispatch Logic (Centralized Routing)

Instead of duplicating event code, push a universal event into dataLayer:

dataLayer.push({
  event: "ecommerce_event",
  action: "purchase",
  order_id: "12345",
  value: 199.99,
  consent_analytics: '{{JS - Consent Analytics}}',
  consent_ads: '{{JS - Consent Ads}}'
});

Then build separate tags for GA4, Ads, Meta, etc., each using:

• The same trigger: ecommerce_event
• With conditions on consent_analytics or consent_ads

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📊 Step 6: Testing Consent-Based Event Routing

Tool	Use
GTM Preview Mode	Ensure event routing based on consent
DevTools > Console	Run gtag.get('consent', 'default')
Google Tag Assistant	Validate tag fire status with consent logs
Real-time GA4 DebugView	Confirm events only appear post-consent

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🧪 Bonus: Push Consent Info into GA4 as Parameters

You can send consent context into GA4 for visibility:

gtag('event', 'purchase', {
  consent_analytics: '{{JS - Consent Analytics}}',
  consent_ads: '{{JS - Consent Ads}}'
});

This helps in reporting opt-in vs opt-out conversion performance.

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