Guide · UK & EU
Google Consent Mode v2: how to check it really works
A broken setup quietly loses your ad conversions or tracks people who said no. Here are the five things to get right, and how to test each one.
The checklist
1. Set all four signals to 'denied' by default
Consent Mode v2 uses ad_storage, analytics_storage, ad_user_data and ad_personalization. For visitors in the UK and EEA, each should start as 'denied' until the visitor agrees.
PECR Reg. 6 · ePrivacy Art. 5(3)
Check your consent signals →2. Don't let tags set ad cookies before consent
Even in Advanced mode, Google tags may send cookieless pings before consent, but no advertising cookies or other trackers should load until the visitor accepts.
PECR Reg. 6 · GDPR Art. 7
Test for pre-consent trackers →3. Update the signals when the visitor chooses
When someone accepts or rejects, your banner must send a consent update. If it doesn't, Google keeps treating everyone as 'denied' (lost conversions) or 'granted' (a legal risk).
GDPR Art. 7
Check your consent update →4. Make rejecting as easy as accepting
A 'Reject all' button should sit alongside 'Accept all' on the first layer of the banner, with equal prominence.
UK GDPR Art. 7 · ICO guidance
Test your cookie banner →5. Test it yourself in the browser
Open your browser's developer tools, go to the Network tab and filter for 'collect' or 'google'. Requests carry a 'gcs' parameter: G100 means ads and analytics denied, G111 means both granted. Check it before and after clicking your banner.
Practical check
Common questions
- What is Google Consent Mode v2?
- It's Google's way for your cookie banner to tell Google tags whether a visitor agreed to advertising and analytics. Version 2 added two signals, ad_user_data and ad_personalization.
- Is Consent Mode v2 required?
- Google requires it for advertisers who want to keep measurement, remarketing and audience features for visitors in the EEA and UK. It doesn't replace the legal need to get consent first.
- What's the difference between Basic and Advanced mode?
- In Basic mode Google tags don't load at all until consent. In Advanced mode they load with signals set to 'denied' and send cookieless pings that Google uses for modelling.