Consent Mode V2

What Consent Mode V2 does

When a user lands on your EU site, your CMP collects their consent choices. Consent Mode V2 is the protocol that broadcasts those choices to Google’s tags (gtag, GTM, Google Ads, Floodlight, GA4) and tells them how to behave.

The four required signals (added in V2):

• ad_storage, can advertising cookies be set?
• analytics_storage, can analytics cookies be set?
• ad_user_data, can user data be sent to Google for ads?
• ad_personalization, can data be used for personalised ads?

Each can be granted or denied. Google’s tags read the state and adjust what they do accordingly.

What happens on consent denial

In a pre-Consent-Mode world, denying cookies meant the pixel didn’t fire at all and Google saw nothing. In Consent Mode V2:

• No personal data is sent when consent is denied
• A small “consent-denied ping” still fires, telling Google that an event happened (but without identifiers)
• Google models the missing conversions by extrapolating from the consenting users to the non-consenting cohort
• You still get conversion reporting, modeled, not measured, but useful for optimization

The modeling is imperfect (it’s a statistical estimate) but it’s far better than the zero you’d get without Consent Mode.

Why V2 was mandatory

Google made Consent Mode V2 mandatory in March 2024 because GDPR + the EU’s Digital Markets Act forced more granular consent. The two new signals (ad_user_data, ad_personalization) exist specifically to give EU users separate controls over data transmission and personalization.

Running Google Ads in the EU without Consent Mode V2 since then means:

• Cannot create new EU audiences
• Cannot use EU data for personalization
• Reduced reporting fidelity

How to implement

Three pieces have to align:

1. A CMP, Cookiebot, OneTrust, Iubenda, Usercentrics, or similar. Captures user choices.
2. CMP-Google integration, the CMP pushes consent state into the dataLayer in the form Google expects.
3. Google Tag, reads dataLayer.consent and adjusts behavior per signal.

The setup is reasonably mechanical. The harder part is making sure your CMP and Google Tag are correctly wired and tested.

Common mistakes

• Setting all four signals to granted regardless of actual consent. Violates GDPR. Auditable.
• Forgetting the default state. Consent Mode needs an initial default consent state (typically denied in EU) before the user interacts with the banner.
• Not testing with consent denied. The modeled-conversion fallback path is where most setups silently break. Test both states explicitly.

FAQ about Consent Mode V2

What is Consent Mode V2?

Consent Mode V2 is Google’s framework for transmitting user consent signals to its ad and analytics services. It passes four signals, ad_storage, analytics_storage, ad_user_data, ad_personalization, so Google tags know what they are allowed to do.

Is Consent Mode V2 required?

Yes for EU campaigns. Google requires Consent Mode V2 for serving ads to EU users since March 2024. Without it, you lose audience and personalisation features in Google Ads.

What happens when consent is denied?

No personal data is sent, but Google still receives a small consent-denied ping. Google uses these pings to model the missing conversions statistically, so reporting fidelity is partly preserved even without consenting users.