Consent Mode v2: what it does and what it cannot fix
Consent Mode v2 is not a cookie banner. It is the mechanism that passes a visitor’s choice to Google tags. If that flow is wrong, reporting may be incomplete or tags may ignore the choice shown on the banner.
In short
The banner asks for consent. Consent Mode passes the answer to Google Analytics and Google Ads. It does not replace the banner, a privacy policy or legal advice. It also cannot recover every missing data point.
Start by separating two jobs
A consent management platform, or CMP, displays the banner and records the visitor’s choice. Consent Mode uses that choice to control Google tags. You need both parts for a complete setup.
For example, a visitor rejects analytics cookies. The site should send analytics_storage=denied. A banner saying “rejected” changes nothing if the tag never receives that signal.
What v2 added
Version 2 added ad_user_data and ad_personalization. The first covers consent to send user data to Google for advertising. The second covers personalised advertising.
Each signal needs a granted or denied value that matches the visitor’s choice. The older analytics_storage and ad_storage signals still matter too.
Basic and advanced mode
In basic mode, Google tags are blocked until consent is granted. After rejection, they send no data. This is simpler, but gives Google less information for conversion modelling.
In advanced mode, tags load with a default denied state. They may send signals without advertising identifiers or cookies. Google can use those signals for modelling when the account meets its data thresholds.
Advanced mode does not mean consent was granted. It still has to respect the visitor’s choice. The setup should be agreed with whoever is responsible for privacy and legal compliance.
What Consent Mode cannot do
It cannot write a compliant banner, decide which permissions are needed, fix a broken GA4 event or repair a form that never fires a tag. It also does not guarantee modelled data for a small website.
GA4 behavioural modelling has volume thresholds. If there are not enough denied events and consented users, the model may never appear.
How to test it
Use Tag Assistant for three checks: before a banner choice, after acceptance and after rejection. Check all four consent signals and confirm that the update happens before events are sent.
Repeat the test on several pages, on a return visit and after changing an earlier choice. A common problem is a landing page that loads tags in a different order from the home page.
What an audit should record
A useful audit says more than “Consent Mode works”. It records the signals in use, their defaults, the update timing, tag behaviour after rejection and evidence from Tag Assistant.
That makes it possible to separate a consent problem from a GTM, GA4 or conversion problem.