Is Your Cookie Banner Blocking Google Ads Tracking?

Cookie banner problems are one of the biggest causes of lost conversions in Google Ads — because they directly change whether tags fire, whether consent updates are sent, and whether attribution signals are allowed.

The most common failure pattern isn't "no banner" — it's a banner that looks fine, but consent never updates or tags remain blocked even after accept.

Symptoms (what you see)

• Conversions drop after CMP/banner changes
• Accept/Reject buttons work visually, but tracking behavior doesn't change
• Tags are blocked even after accept (or tags fire before consent)
• GA4 shows events, but Google Ads attribution is weak or missing

Why it happens

• Consent not updating: the CMP collects a choice but never calls Consent Mode update
• Tags blocked after accept: consent mode is granted but GTM/gtag triggers remain gated incorrectly
• CMP misconfiguration: wrong mapping of categories → Consent Mode signals (ad_storage, analytics_storage, etc.)
• Timing issues: Consent Mode defaults set too late; tags fire before consent state exists

Fix checklist

1. Verify the consent update event: confirm accept/reject triggers a real update in your implementation
2. Check gcs values: verify network requests reflect correct consent state after accept/reject
3. Test accept vs reject behavior: cookies and requests should differ; accept should enable what reject blocks
4. Confirm Consent Mode v2 is correct: defaults before tags; updates after user action; correct signal set

For the bigger picture, see why conversions break and the GA4/Ads mismatch guide here.