How to check Google Consent Mode v2: is it set up correctly, and why are conversions dropping?

Last updated: October 25, 2026

Google Consent Mode v2 isn’t a banner: it passes the choice your visitors make in your consent banner on to Google’s tags. You check it in Tag Assistant, Google’s free debugging tool at tagassistant.google.com, where all four consent parameters need a default state before the first measurement, for example “denied”, and then need to update to match the visitor’s choice. If the conversions reported in Google Ads are dropping, the reason can be fewer visitors consenting, a tracking error or simply fewer orders, and Google only estimates missing conversions when certain requirements are met.

We only explain the technical side here. Whether your consent setup meets legal requirements is a question for your data protection officer or a legal advisor.

A quick check in four steps

Before each test, close all private (Incognito) windows and open a new one. In Chrome, cookies stay in place as long as any Incognito window is open, so an earlier banner choice could carry over. These checks are necessary but not sufficient: four correct values don’t prove that every tag on your site respects the choice.

1. Connect your site in Tag Assistant. Click “Add domain”, enter your website URL and click “Connect”. If it won’t connect, possible causes are a missing Google tag, an ad blocker, a consent tool that blocks Google tags, or a tag inside an iframe (a page embedded from somewhere else), which Tag Assistant can only debug if its Chrome extension is also installed. With the basic implementation (Basic, see below), Google tags only load after the click in the banner. In that case no consent event appears before the choice, and you connect the page after accepting.
2. Check the default state. With Advanced, don’t accept yet. With Basic, you already did in step 1, which is how Google’s own guide does it, too. Under “Summary”, select the earliest event of the type “Consent” and look at the “API Call” section: ad_storage, ad_personalization, ad_user_data and analytics_storage must be set, for example to “denied”. You can also find the values under “Output” in the “Consent” tab, in the “On-page Default” column. Check that this consent event comes before the first measurement events, because Google requires the default state to be set before any measurement commands.
3. Accept and check the update. Accept all options in the banner. Then select the latest “Consent” event: the same four parameters should now be “granted”, or you see it in the “On-page Update” column. If you use Tag Manager, the “Tags” tab under “Summary” shows whether a tag behaved according to its consent settings. Then open a second page of your store: an early update with your choice should follow there without the banner appearing again.
4. Decline and check again. Close all private windows, open a new one, connect the page and decline in the banner. With Advanced, check the default state as in step 2 and then the latest “Consent” event: all four parameters should stay “denied”, and the tags send only cookieless pings (see below). With Basic, Google tags shouldn’t load at all after a decline, so no Google consent event is expected. Only this test shows how your site behaves when a visitor declines. To cross-check in Google Ads, click “Goals”, open the “Conversions” drop-down and click “Summary”, then click a Google Ads website conversion action and open the “Diagnostics” tab. Google names two statuses there: “Consent mode is implemented” and “Consent mode is implemented and modeling is active”. Google says the status can take 48 hours to appear, and up to two weeks in certain cases.

If your banner offers separate categories, also test a mixed choice, for example allowing analytics but rejecting advertising, and check that only the matching parameters change to “granted”. Then reopen the banner’s settings, withdraw your consent and check that an update with “denied” follows. If your default settings differ by region, keep in mind that the check only shows the behavior for the region you’re testing from.

What consent mode is and what it isn’t

Google is explicit about this: consent mode doesn’t have its own banner or widget. The choice comes from your cookie banner, or more precisely from the consent management platform (CMP) that displays it. Consent mode passes that choice on. The Google tag, Google Analytics, Google Ads, Floodlight (another Google measurement tag) and the Conversion Linker have consent checks built in. For other tags in Tag Manager, you set this up in the tag configuration under “Advanced” > “Consent Settings”.

The four parameters:

• ad_storage controls storage, such as cookies, related to advertising.
• analytics_storage controls storage, such as cookies, related to analytics, for example for visit duration.
• ad_user_data controls whether user data related to advertising may be sent to Google. Google says it’s required for measurement such as enhanced conversions (hashed first-party customer data) and tag-based conversion tracking.
• ad_personalization controls consent for personalized advertising, such as remarketing (ads shown to past visitors). For personalized advertising, ad_user_data and ad_personalization both need to be “granted”.

The last two were added with version 2. Google says consent mode users need to send both in addition to the first two, and for traffic from the European Economic Area (EEA), it requires that consent choices be passed to Google.

Basic or Advanced

With Basic, Google tags only load after the visitor has interacted with the banner. If the visitor declines, nothing is sent to Google, not even the consent state. Modeling then uses a general model. With Advanced, tags load as soon as the visitor opens the page, with a default state that you set and that can differ by region (Google mentions the EEA, Switzerland and the United Kingdom). If the visitor declines, cookieless pings are sent: small messages to Google that don’t set or read cookies. If the visitor consents, cookies are set and all measurement data is sent. Modeling then uses an advertiser-specific model, one built for your account.

The pings include, among other things, a timestamp, the user agent (the browser’s identifier), the referrer (the previous page), information about the consent state and the consent tool used, and a random number generated on each page load. For privacy reasons, Google says a data threshold applies, but the help page doesn’t give a number.

Common errors and how to fix them

These points come from Google’s guides, plus what we’d check:

• The default state comes too late. On every page, the default state must be set before any commands that send measurement data, such as config or event. With gtag.js, that’s the command gtag('consent', 'default', …). With Tag Manager, your CMP’s template or a consent template sets it. Check what’s already in place before adding a second default. If your CMP loads asynchronously, the optional value wait_for_update can give it time to update the state. Check the order in Tag Assistant (step 2).
• No update follows the choice, or the choice isn’t stored, so later pages don’t send an update with the stored choice after loading. The update should fire as soon as the visitor responds in the banner, and the choice should be stored. Check this in step 3 and in your CMP’s settings.
• The update uses the wrong method. For sites using Tag Manager, Google recommends letting a CMP handle the updates, through its template or a custom template using updateConsentState, and advises against using gtag('consent', 'update', …) instead of updateConsentState. So check whether your CMP’s template is active.
• Tags are blocked until the choice is made. This is intended with Basic and not an error. Google points out, however, that if Google tags are blocked until the visitor interacts with the banner, it can’t verify the visitor’s consent choices, and that this can lead to data loss. If you don’t want that, you can choose Advanced after checking with your data protection officer. Google also says it is strengthening enforcement of its EU user consent policy for EEA traffic.

Why reported conversions can drop

Without consent, the tags measure less. With Basic, the whole visit is missing; with Advanced, only cookieless pings arrive. Google tries to close the gap with modeling and includes the estimated conversions in the “Conversions” column. The help page names two requirements for this: consent mode is implemented correctly (or the IAB Transparency & Consent Framework, TCF v2.0, an advertising industry consent standard), and there is a click threshold that Google states as 700 ad clicks over a seven-day period, per country and domain grouping (Google’s two help pages word this slightly differently). Once both are met, Google says its models enter a training period before modeled conversions show up. The “Diagnostics” tab shows whether your account has reached that point. As long as it only says “Consent mode is implemented”, Google explains that consent mode is in place but the thresholds for conversion modeling haven’t been met yet.

How much your reported conversions drop depends on how many visitors consent. Comparing the trend in your store’s orders with the trend in your Google Ads purchase conversions helps you tell a drop in sales from a gap in reporting, but it doesn’t identify the cause on its own. If orders are stable, check your consent rate, your purchase tracking and any recent changes to campaigns or conversion settings. Google’s help page shows a worked example with numbers; we don’t repeat them here because they describe that example, not your account.

How we set it up on adsberater.de

On our own site, the default state for ad_storage, analytics_storage, ad_user_data and ad_personalization is set to “denied” in the page source before Cookiebot loads as our consent tool, and Google Tag Manager only loads after that. In addition, wait_for_update is set to 500 milliseconds. Use the steps above to check whether the order is right on your site.

What can’t be checked from the outside

In the browser, you can check which default state your site sets, whether an update follows the choice and whether Google tags load after a decline. You can also spot extra tracking scripts and requests that don’t come from your Tag Manager container. How many visitors consent on your site, and how your CMP and container are configured in detail, can only be seen with access to your Tag Manager, your CMP’s settings and your consent statistics.

More questions

Basic or Advanced: what's the difference?

With the basic implementation (Basic), Google tags only load after the visitor makes a choice in the banner, and nothing is sent without consent. With the advanced implementation (Advanced), tags load on the first page view with a default state and, without consent, send only cookieless pings that Google can use to model conversions. Whether modeling is actually active for your account depends on further requirements (see above). Which option fits your banner and your requirements is a question for your data protection officer.

How long does it take for Google Ads to show the status?

According to Google, the status can take 48 hours to appear in Google Ads, and up to two weeks in certain cases. If you've checked in Tag Assistant that your setup works correctly, Google says you can attribute any remaining alerts or a missing status to this delay. If Tag Assistant shows something wrong, the setup itself has an error. If the status is still missing after two weeks, check the setup again.

Is a cookie banner without consent mode enough?

The banner collects the choice, and consent mode passes it on to Google's tags. For traffic from the European Economic Area, Google states that consent must be obtained and passed to Google if you use personalized ads and measurement. A banner that doesn't pass the choice on leaves Google's tags without consent signals, and that doesn't mean they stop sending data. So check both the consent signals and how the tags behave. Whether your setup meets the requirements is a question for your data protection officer.

Related questions

• Is server-side tracking worth it for a small online store?

Sources

1. About consent mode, Google Ads Help, retrieved October 25, 2026
2. Consent mode overview, Google for Developers, last updated July 30, 2026
3. Set up consent mode on websites, Google for Developers, last updated October 13, 2026
4. Troubleshoot consent mode with Tag Assistant, Google for Developers, last updated October 13, 2026
5. About consent mode modeling, Google Ads Help, retrieved October 25, 2026
6. Verify consent mode implementation, Tag Manager Help, retrieved October 25, 2026
7. Updates to consent mode for traffic in European Economic Area (EEA), Google Ads Help, retrieved October 25, 2026
8. Consent mode reference, Google Ads Help, retrieved October 25, 2026
9. Troubleshoot with Tag Assistant, Tag Assistant Help, retrieved October 25, 2026
10. Browse in Incognito mode, Google Chrome Help, retrieved October 25, 2026

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