Consent Mode v2 introduced four signals that control how Google's tags behave based on user consent choices. Many practitioners treat these four signals as a single on/off switch, but they serve fundamentally different purposes: two control analytics data collection, and two control advertising data usage. Confusing them leads to setups that are either over-collecting (a compliance risk) or under-reporting (a performance risk). This article explains what each signal does, how Analytics and Ads behaviour can diverge based on signal state, and why Google Signals should not be treated as a substitute for consent controls.
The four consent mode v2 signals
- analytics_storagecontrols whether GA4 can store and read cookies and identifiers for analytics purposes. When denied, GA4 cannot set the_ga cookie, cannot link pageviews to a persistent user, and cannot maintain session continuity. Tags still fire anonymised cookieless pings that enableconsent-mode conversion modeling.
- ad_storagecontrols whether advertising-related storage (cookies, identifiers) can be used on the device. When denied, Google Ads and GA4 cannot use theGCLIDcookie or other advertising identifiers. Attribution and conversion tracking degrade. Tags send limited signals without identifiers.
- ad_user_datacontrols whether personal data can be used for advertising purposes, including enhanced conversions which hash and send first-party data like email addresses to Google for conversion matching. When denied, enhanced conversions cannot operate even if the user accepts other tracking.
- ad_personalizationcontrols whether user data can be used for remarketing and personalised advertising. When denied, a user can still be counted for conversion reporting but cannot be added to remarketing audiences or shown personalised ads based on their browsing behavior.
How GA4 behaves differently from Google Ads under denied consent
When analytics_storage is denied, GA4 enters a cookieless measurement mode. The GA4 tag still fires and sends anonymised event data including page view counts, interaction timings, and consent state, without any persistent user identifier. GA4 uses these signals, combined with data from consented users, to estimate user counts and session metrics through behavioral modeling. The result appears in your GA4 reports as normal data, you cannot tell which data points are observed versus modeled unless you hover over or click the data quality indicator (shield icon) in the report header. This is a frequent source ofdiscrepancy between GA4 and Google Ads numbers.
When ad_storage is denied, Google Ads conversion tracking operates without access to the GCLID or advertising cookies. Reporting and optimization may rely more heavily on Google's consent-aware advertising modeling behavior, but the exact output depends on the account, implementation, and product configuration in use.
The practical takeaway is simpler: analytics reporting and advertising reporting can diverge under denied consent even when both products are configured correctly, so teams should review each path separately instead of assuming one setting controls everything.
Unsure whether your Consent Mode signals are correctly configured?
Why analytics and Ads consent should be reviewed separately
Teams sometimes treat Google Signals, GA4 reporting settings, and Consent Mode as if they were one combined privacy control. They are not. Consent Mode manages how tags behave based on the user's choice — for the full implementation walkthrough, see ourConsent Mode v2 guide. Google Signals is a separate GA4 feature that affects certain reporting and audience capabilities inside Google's ecosystem.
The safest audit posture is to validate the site's consent signals directly, then separately review any GA4 or Google Ads features that depend on those signals, alongside your broaderGDPR and GA4 compliance review. Do not assume a product toggle is an advertising-consent control unless the current Google documentation says so explicitly.
Consent mode vs Google signals: they are not the same thing
A persistent source of confusion is treating Google Signals and Consent Mode as equivalent. They are not. Consent Mode manages how your tags behave based on user choice, it is a technical framework that sits between the user's browser and Google's servers. Google Signals is a GA4 feature that allows GA4 to associate user data with Google Account information for cross-device tracking and demographics reporting. Disabling Signals does not disable Consent Mode, and enabling Consent Mode does not enable Signals. They operate independently.
Analytics modeling vs Ads modeling: the key difference
GA4 behavioral modeling uses observed data from consenting users on your property to estimate the behavior of non-consenting users when the relevant prerequisites are met. Google Ads conversion modeling under denied ad_storage may rely on a different mix of signals and product logic. The exact behavior can change over time, so avoid treating one model as a permanent proxy for the other.
Consent mode signal summary
Understanding which signal controls which system is the first step to auditing your implementation. Use the checklist below as a quick reference for what each denied state actually causes.
Consent mode signal summary
- analytics_storage denied → cookieless pings → GA4 behavioral modeling fills gaps
- ad_storage denied → no advertising identifiers → Ads conversion modeling (less accurate)
- ad_user_data denied → enhanced conversions blocked → first-party match rates drop
- ad_personalization denied → user excluded from remarketing audiences → audience sizes shrink
- Google Signals and Consent Mode should be reviewed as separate controls
- For regions where explicit consent is required (EEA, UK), all four signals should default to 'denied' and update on explicit user consent
Related guides to read next
Consent Mode V2 Caused Unassigned Traffic? How to Diagnose It
Why Consent Mode implementation causes attribution loss and the steps to diagnose and reduce Unassigned traffic.
Consent Mode vs BigQuery: Why Exported Data Still Looks Wrong
Why BigQuery data diverges from GA4's UI when Consent Mode is involved and how to build reliable reporting on top of it.
Audit your consent mode configuration
GA4 Audits checks all four consent signals, your CMP integration, and whether behavioral modeling thresholds are met.