What exactly changes on June 15
Until now, two mechanisms controlled the ad data flowing between Google Analytics 4 and Google Ads:
- Google Signals in GA4 (a legacy on/off toggle)
- Consent Mode V2 via the
ad_storageparameter (the modern system based on visitor consent)
From June 15, 2026, Google removes the first. Google Signals still exists, but it now only controls GA4 reporting (who can see what in your reports). For Google Ads, only ad_storage decides whether ad data flows or not.
The PPC Land sentence sums it up: "From 15 June, only the cookie banner does that job."
Starting June 15, 2026, GA data flow is controlled by Google Signals but Google Ads is handled exclusively by the ad_storage consent mode setting. Either grant ad_storage and Google will use all available ads signals at their disposal (including linking the user with their Google sign-in), or set it to denied and Google will not access any identifiers apart from what's available in the URL (e.g. gclid). There's no middle ground here. This does place more stress on your consent mode implementation, so make sure the update calls are done appropriately and contain the correct signals.
The 4 parameters to know by heart
Consent Mode V2 uses 4 independent signals. Each one controls a different aspect of tracking. You have to know what each one does and what your default is in Quebec (Law 25 = opt-in, so denied by default).
The 4 Consent Mode V2 parameters
| Parameter | What it controls (Google verbatim) | Recommended default in Quebec |
|---|---|---|
| ad_storage | Ad-related storage (ad cookies, device identifiers). This is THE key parameter after June 15. | denied |
| ad_user_data | Sending user data to Google for advertising purposes. | denied |
| ad_personalization | Consent for personalized advertising (remarketing, custom audiences). | denied |
| analytics_storage | Analytics storage (visit duration, basic GA4 sessions). | denied |
The verification procedure, at a high level
Google published an official validation procedure built on Tag Assistant. On paper, it looks like a 6-step visual check: open the site, intercept the gtag('consent', ...) requests, verify each parameter's value. In practice, the value isn't in the checklist itself, it's in spotting where the visible values do NOT match what GTM is actually sending, or in detecting a race condition between your CMP, your dataLayer, and the gtag.js event. That's where most implementations fail silently, with no visible error in the console.
Official verification procedure (Tag Assistant)
Open Tag Assistant and enter your site URL
Go to tagassistant.google.com, click "Add domain", paste your site URL, click "Connect". A tab opens. Accept your cookie banner like a normal visitor.
Check the earliest "Consent" event
In Tag Assistant, go to the Summary tab. You'll see a list of events. The first event should be a Consent default (before any other event). Click it. In the API Call section, verify that all 4 parameters
ad_storage,ad_user_data,ad_personalization,analytics_storageare all present and explicitly set to "denied". If any is missing, that's a major problem.Check the most recent "Consent" event
Still in Summary, scroll down to the Consent update event (which fires after you clicked your banner). Verify that the values reflect your choice: if you accepted all →
grantedeverywhere. If you refused →deniedeverywhere. If you made a custom choice → mix per your banner.Check each tag individually
In Summary > Tags tab, click each tag (Google Ads, GA4, Floodlight). Verify each behaved according to consent: if you refused
ad_storage, your Google Ads tag must NOT have sent identifiers. If you accepted, it must have sent everything. Any divergence = bug.Establish your 30-day baseline before June 15
Before June 15, export to a Google Sheet: your conversions per day for the last 30 days, the size of your remarketing lists, the number of unique users. That's your reference. If after June 15 you see a drop greater than 5-10%, your banner has a bug.
To check before June 15 (full audit)
- Identify exactly where visitor choices are captured (CMP), stored (cookie, localStorage), and translated into Google signals
- Confirm all 4 parameters have explicit defaults (`denied` in Quebec)
- Test with Tag Assistant in "refuse", "accept all", and "custom choice" states
- Verify that `consent default` runs BEFORE any measurement command
- Save a 30-day baseline (conversions/day, remarketing list size, unique users)
- Document defaults by region if you target outside Quebec (EEA, US, etc.)
The Quebec angle: Law 25 gives you a head start, provided your banner is technically correct
Since 2023, Law 25 already requires you to have an explicit consent banner (opt-in, not opt-out). If you or your agency did the work properly back then, you are probably ready for June 15 by accident.
But "probably" isn't enough. Law 25 legal compliance ≠ correct Consent Mode V2 technical implementation. McCarthy Tétrault reminds us that Law 25 provides for fines up to $25M or 4% of global revenue for serious consent violations. Grant Thornton recommends testing your banner with a tool like Tag Assistant to validate that the technical mechanic follows the legal promise.
The good news: a Quebec SMB that already invested in its Law 25 banner is probably 70-80% of the way there. June 15 requires verifying the remaining 20-30%, not redoing everything.
Google just quietly removed one of the most important privacy controls advertisers had in Google Analytics. And they framed it as "simplifying." So your options are: let Google collect more data for its ad business, or accept degraded campaign performance. Pick one. Google is also offering a 90-day grace period to update privacy disclosures. If nothing meaningful were changing about how user data is handled, why would disclosures need updating? This looks less like simplification and more like Google moving the levers to where they benefit Google the most, which is their Ads business.
-90%
Documented conversion drop
Teasdale case, misconfigured banner
60%
Data lost forever
No retroactive recovery after detection
0 days
Of warning before degradation
The banner breaks silently
Verdict
The official procedure exists, and it is documented. What is NOT documented is the combinatorics of traps: GTM race conditions, Law 25 configurations that force an initial state different from what Google expects, CMPs that rewrite the dataLayer after load, authentication redirects that strip consent parameters at the wrong moment. We've identified 10 across the last 20 client audits. The technical guide lists them all with the exact fix.
Who should run this verification: a senior GA4 + GTM person who has already seen a consent race condition in production, who can read gtag('consent', ...) in the Network tab and understands why Google's default state and the Law 25 default state don't align out of the box. Without that profile in your team, the operational risk isn't the time it takes to tick the boxes: it's the month where your CPA jumps 30% and no one connects the dots back to a GTM line in the wrong order. That is exactly the silent bug class we operate on retainer for our clients.
If you already work with an agency, the question to ask: "Did you test our banner with Tag Assistant in 'refuse' and 'accept all' modes? Are the 4 parameters all denied by default? Did you baseline our GA4 and Google Ads conversions over the last 30 days for a post-June-15 comparison?" A serious agency has already done all three and can give you screenshots.
Want us to audit your Consent Mode V2 implementation before June 15?
Request an audit (1h, free)Frequently asked questions
My site has no cookie banner. Should I worry about June 15?
Yes, doubly. First, you're probably in violation of Law 25 since 2023 (fines up to $25M). Second, from June 15, with no banner, Google will apply its automatic defaults. These defaults may be more permissive OR more restrictive than what you want. You no longer have any control.
I use a free CMP (e.g. Complianz, CookieYes free). Is that enough?
Probably yes for Law 25 compliance, but not guaranteed for Consent Mode V2. The free tier of many CMPs doesn't include the "Google Consent Mode V2 intégration" feature. Check in the CMP settings that Consent Mode V2 is explicitly mentioned and that all 4 parameters are sent. If not, consider a paid upgrade (~$10-30/month) or a migration to Cookiebot/OneTrust.
How many conversions will I lose if I do nothing?
Observed cases: 5% to 30% drop in tracked conversions in Google Ads for sites with a correct banner but Google Signals previously ON (the loss is in attribution precision). For sites with a misconfigured banner: up to 90% drop (the Teasdale case). The range is wide because it depends on how many users click "refuse".
If I set `ad_storage` to 'granted' by default, does that fix the problem?
No, do NOT do that. First, it's illegal in Quebec (Law 25 = explicit consent = denied default). Second, it's technically an implicit opt-out disguised as opt-in, which is exactly what Google considers "misconfiguration" and risks sanctions on your Google Ads account (already observed in 2025 for UK/EEA accounts).
Will Smart Bidding readjust automatically after June 15?
Yes, but after a 2 to 3-week learning period. During that time, expect more variance in performance. Avoid pushing major budget changes between June 15 and July 5. If your conversion data suddenly becomes too sparse because your banner is in mass "refuse" mode, consider activating Enhanced Conversions as a lifeline for Smart Bidding.