Google Consent Mode v2 Troubleshooting: Top 10 Mistakes and How to Fix Them

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If you’re doing business in the EU or EEA and want to use Google services (GA4, Google Ads, gtag and Google Tag Manager), you need to implement Google Consent Mode v2; otherwise, Google services will not function. You also need to use a Google-certified CMP for consent management.

If Google Consent Mode v2 isn’t configured correctly, your website may still show a Cookie Banner, but Google may not receive the right user consent signals. That means Consent Mode v2 is not working, so Google Ads, GA4, remarketing, conversion tracking, and enhanced conversions will be affected.

You need to perform Google Consent Mode v2 troubleshooting because you might not notice the wrong configuration right away. The tags may still fire, reports may still collect data, and you could collect data about user interactions with your marketing campaigns. But the data behind them can become incomplete, inconsistent, or wrong.

Read this Google Consent Mode troubleshooting guide to test Google Tag Manager Consent Mode v2.

What Is Google Consent Mode v2 and Why Troubleshooting Matters

Google Consent Mode is a tool that includes an application programming interface (API) to control tag cookie storage, which allows businesses to send user consent preferences from cookie banners to Google.

Google Consent Mode adjusts how Google tags like Google Tag Manager, Google Analytics, Google Marketing Platform, and Google Ads perform based on user consent.

Google Consent Mode v2 adds two new user consent states:

  • ad_user_data It is used to set consent for sending user data to Google for advertising purposes.
  • ad_personalization It controls whether data can be used for ad personalization (e.g. remarketing)

 

Google Consent Mode v2 is especially important for websites that serve EEA traffic, use Google advertising products, or rely on consent-based measurement. 

The setup needs to pass the correct consent states, including ad_storage, analytics_storage, ad_user_data, and ad_personalization. If one of these is missing, delayed, or mapped to the wrong banner category, Google may treat the user as if they did not give consent for certain advertising or analytics cookies. This will affect the efficiency of Google products and raise compliance risks.

Small setup mistakes can create bigger issues later, significantly affecting Google analytics results and marketing campaigns. Thus, it is essential to test Google Consent Mode v2 after implementation.

A working setup should send default consent states before Google tags run, update those states after user interaction, and show the expected consent parameters in debugging tools like Google Tag Assistant. 

CookieScript CMP is a Google-certified CMP. It integrates with Google products, is listed in Google’s certified CMPs, and is recommended by Google for implementing Google Consent Mode v2. It's also valued by users. In 2025, CookieScript received its fourth consecutive badge in a row as the leader on G2, a peer review site, and became the best CMP on the market for a whole year! 

Read also why Google Consent Mode v2 impacts ad revenue. 

Mistake #1: Consent Mode v2 Is Not Installed at All

There could be many Consent Mode v2 errors.

The most obvious mistake with Google Consent Mode v2 is simply not installing it.

Many website owners assume that having a Cookie Banner and a Consent Management Platform (CMP) is enough. It is not.

A Cookie Banner collects the visitor’s cookie choice, which has to be passed to Google services, such as Google Ads, GA4, Floodlight, and other Google tags.

If Google Consent Mode v2 is not installed, Google services simply will not receive the consent signals they need, even if a website has a banner and collects user consent.

This problem usually happens when a CMP is installed, but Google Consent Mode is not enabled inside the CMP settings.

It can also happen when the site has Google Tag Manager, but no consent configuration is created inside the GTM container.

How to fix it

First, use a CMP that supports Google Consent Mode v2.

Google maintains a list of Google-certified CMPs, which should be used for your consent management. Google also evaluated certified CMP Partners and classified them into 3 tiers: Gold, Silver, and Bronze.

CookieScript CMP is a Google-certified CMP with the GOLD Tier in the Google Tiering System. It supports Google Consent Mode v2 and IAB TCF v2.2 integration. 

Second, enable the Consent Mode integration in your CMP settings.

See instructions on how to implement Google Consent Mode v2 to your website:

Mistake #2: Missing ad_user_data and ad_personalization Consent Signals

In 2024, Google Consent Mode v2 introduced two additional consent signals: ad_user_data and ad_personalization.

Users had to update their consent mode to the new version, Consent Mode v2.

If your website still uses an older version of consent mode, it may have only two consent signals (ad_storage and analytics_storage) and miss the two newer parameters (ad_user_data and ad_personalization).

If these signals are missing, Google Ads may not receive enough consent information for certain advertising features. It will be impossible to do remarketing in Google Ads, Floodlight, and Display. This could significantly affect the measurement results, the performance of advertisers’ remarketing and engagement campaigns, and produce warnings in Google Ads or Tag Assistant.

How to fix it

Update your CMP to Google Consent Mode v2. 

A proper setup should include these four key Google consent signals:

  • ad_storage
  • analytics_storage
  • ad_user_data
  • ad_personalization

 

Read more for details:

Mistake #3: Consent Defaults Are Set Too Late

Consent Mode needs a default consent state before Google tags start running.

A common mistake is setting consent defaults after GTM loads other tags. In that case, Google tags may read the consent state before any default was set. Tag Assistant may show a warning like “a tag read consent state before a default was set.”

During this misconfiguration, your Google tags may start working before they know whether consent is granted or denied. That can cause inconsistent behavior. Sometimes tags may behave correctly; sometimes they may fire too early, ignoring user consent choice.

How to fix it

Set consent defaults as early as possible.

In Google Tag Manager, consent defaults should usually be handled with the trigger Consent Initialization - All Pages. This trigger is set to run before regular pageview tags and other triggers.

Your default consent state should normally be set before Google Analytics, Google Ads, remarketing, or conversion tags fire.

A typical setup should be:

  • Set default consent state first.
  • Load the CMP.
  • Wait for the user’s cookie choice.
  • Send a consent update.
  • Allow Google tags to behave based on the updated consent state.

Mistake #4: Google Tags Fire Before User Consent Is Collected

Another common Consent Mode v2 mistake is when Google tags fire before the visitor has made a consent choice.

This depends on the implementation type. In advanced Consent Mode, Google tags may load before consent, but they should adjust behavior based on denied default consent. In basic Consent Mode, tags should usually be blocked until the user grants the relevant consent.

The problem comes when the setup is neither cleanly basic nor cleanly advanced. Tags fire early, without any proper default consent state.

This could also happen when tags are supposed to wait, but triggers allow them to run immediately.

If Google tags fire before consent is collected, that does not match the user’s consent choice, so it violates data privacy laws.

How to fix it

Select either basic or advanced Google Consent Mode.

For Basic Consent Mode, configure tags so they only fire after users grant required consent.

For Advanced Consent Mode, set default consent to denied where required before tags fire. Google tags can then adjust their behavior when the user makes a choice.

In GTM, review each Google tag and check its consent settings, trigger rules, and firing order.

Read more how to select Advanced or Basic Google Consent Mode v2. 

Mistake #5: A Cookie Banner Does Not Send Consent Updates After User Choice

A working Consent Mode setup sets default consent states before Google tags run and later updates those states after the visitor accepts, rejects, or customizes their cookie preferences. If Google doesn’t receive consent updates, it may continue using the default consent state even after the user makes a choice.

Usually, your default state should be denied. If it remains denied after a user accepts cookies, your website will not track the user. That can impact conversions, remarketing eligibility, analytics data quality, and thus, revenue. https://cookie-script.com/guides/how-google-consent-mode-v2-impact-revenue

The opposite can also happen. Tracking users after they reject Cookie Banner is a serious compliance issue.

How to fix it

Check that your CMP sends a consent update every time users make a cookie choice or change their consent decisions.

Check what happens after user choice. In Tag Assistant, test each banner action separately, when a user presses:

  • Accept all.
  • Reject all.
  • Save custom preferences.
  • Changes consent later through the cookie settings panel.

 

A proper setup should update consent states immediately after the user’s choice.

Mistake #6: Your CMP Is Not Properly Connected to Google Tag Manager

A CMP and Google Tag Manager need to work together. Installing both tools separately is not enough.

The CMP must pass user consent choice into GTM in a format GTM can use. If the GTM doesn’t receive a proper signal, it may not know which tags to block, fire, or update.

This mistake often creates a false sense of security. Everything seems to be working (the banner appears on the website, GTM is installed, a CMP sends Google tags), but the consent signal does not reach GTM correctly, and the user consent choice is not respected.

How to fix it

Use a CMP like CookieScript that supports Google Consent Mode v2 and has a reliable GTM integration.

Test your GTM using a GTM preview mode. 

What to check during the GTM testing:

  • Check whether CMP tag fire early enough.
  • Check whether the CMP sends default and updated consent states correctly.
  • Check whether GTM tags have the correct consent requirements.

 

In GTM Preview mode, click through the consent events and check whether the data layer receives the expected consent values. Then verify the same behavior in Tag Assistant.

Mistake #7: Consent Mode v2 Works on Some Pages but Not Others

Sometimes Consent Mode v2 works on the homepage but fails on product pages, landing pages, checkout pages, or blog posts.

This implementation inconsistency usually means that the CMP is not installed in all templates, GTM may not be installed globally, or certain pages may use hardcoded Google tags outside the main GTM container.

Consent Mode v2 needs to cover the entire website, not just some pages.

If some pages send consent signals and others do not, your tracking becomes inconsistent and it creates compliance risks.

How to fix it

First, test all your web page types to see if Consent Mode v2 is working.

Check:

  • Homepage
  • Blog articles
  • Product pages
  • Pricing pages
  • Checkout or signup pages
  • Campaign landing pages.

 

Make sure the CMP, GTM containers, consent defaults, and consent updates are present everywhere.

Also verify that no Google tags are hardcoded directly into the website. Hardcoded tags can bypass GTM consent settings, leading to inconsistent behavior.

Mistake #8: Region-Based Consent Settings Are Misconfigured

Different privacy laws have different consent requirements. For example, most of U.S. states allow implied consent, while California’s CCPA/CPRA or Europe’s GDPR require explicit consent.

Setting a single cookie banner that satisfies the strictest requirements is not ideal, as you will miss user information when user tracking is allowed. On the other hand, tracking users where it’s not allowed could lead to serious compliance problems.

How to fix it

Make sure you have enabled geo-targeting in your CMP and selected the correct regional configuration in both your CMP and your Consent Mode setup.

Check which countries or regions receive a cookie banner with denied consent by default, and which countries receive a cookie banner with granted consent by default.

Then test cookie banner behavior by simulating different locations. Make sure EEA visitors receive a banner with denied consent by default.

Mistake #9: Google Ads or GA4 Tags Ignore Consent Settings

Sometimes Consent Mode v2 is installed, but individual Google tags still do not follow consent rules.

This can happen when tags have incorrect consent settings in GTM, fire through custom HTML, use old templates, or are placed directly in the website code instead of GTM.

If GA4 or Google Ads tags ignore consent settings, your Consent Mode setup becomes incomplete. If some tags fire independently, this could affect conversion tracking, remarketing tags, and manually added scripts.

How to fix it

Audit all Google-related tags, checking for:

  • GA4 configuration tags.
  • GA4 event tags.
  • Google Ads conversion tags.
  • Google Ads remarketing tags.
  • Floodlight tags.
  • Google tag scripts added directly to the site.
  • Custom HTML tags that load Google scripts.

 

Inside GTM, review each tag’s consent settings. Each tag should have the correct consent settings.

Then run a full test in GTM Preview mode and Google Tag Assistant. Reject cookies on a cookie banner and check what tags fire. Then accept cookies and check what changes.

Read more about how to use GTM preview mode. 

Mistake #10: CMP/GTM Mapping Conflicts Break Consent Signals

The last common mistake is CMP and Google Tag Manager mapping conflicts.

Your CMP may use usual cookie categories, such as “Necessary,” “Analytics,” “Performance,” and “Marketing.” Google Consent Mode v2, however, uses specific consent signals such as ad_storage, analytics_storage, ad_user_data, and ad_personalization.

If these categories are not mapped correctly, the user’s consent choice may be incorrectly translated into the Google consent status. Google tags may receive a different signal than users intended.

CMP/GTM mapping conflicts can affect both compliance and tracking.

For example, a visitor may reject marketing cookies, but poor mapping could still allow advertising tags to behave as if users granted consent.

This usually happens when the CMP does not fully support Google Consent Mode v2 or the CMP is not a Google-certified CMP.

How to fix it

Use a Google-certified CMP that supports Google Consent Mode v2 integration with all required Google consent signals.

Then review how your CMP maps cookie categories.

It should be mapped like this:

  • “Analytics” consent controls analytics_storage
  • “Marketing” or “Advertising” consent controls ad_storage
  • “Marketing” or “Advertising” consent controls ad_user_data
  • “Marketing” or “Advertising” consent controls ad_personalization

 

After updating the mapping, test all banner choices in Google Tag Assistant and check whether Google consent signals update correctly each time:

  • Reject all cookies.
  • Accept all cookies.
  • Save custom preferences.
  • Reopen the banner and change consent.

 

If the consent values in Tag Assistant do not match the user’s cookie choice on a banner, your CMP/GTM mapping still is not working.

CookieScript CMP has the following features, allowing businesses to implement Google Consent Mode v2 seamlessy and avoid Consent Mode v2 errors:

 

CookieScript also offers a 14-day free trial.

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How to Test Google Consent Mode v2 in Google Tag Manager

When Google Consent Mode v2 is implemented correctly, your website should display a cookie banner that sends the user's consent choice to Google. Google receives the correct consent signals before and after the user makes a choice.

A proper Consent Mode v2 test should confirm three things:

  • Consent defaults are set correctly before Google tags fire.
  • Consent updates are sent after the visitor accepts, rejects, or customizes cookies.
  • Google tags behave correctly based on the current consent state.

 

Test Google Consent Mode v2 in Google Tag Manager (GTM) to check if Consent Mode v2 is implemented correctly and Google receives the correct consent signals.

Before testing, you jave to install CookieScript with Google Tag Manager. Then, implement Google Consent Mode v2 with GTM or manually.

To test Google Consent Mode v2 in GTM, perform these steps:

Step 1. Open GTM preview mode

Open your GTM container and click Preview. Enter your website URL and connect the debugging session.

Your website should open in a new tab with Tag Assistant connected. You could see which tags fire, which events happen, and what consent state is active at each step.

 

Step 2. Set correct CMP and GTM triggers for initialization

Your CMP consent trigger should be set on Consent Initialization - All Pages. This trigger is designed for tags that set or update consent before other tags run.

GA trigger should be set to Initialization- All Pages.

The common mistake is selecting the wrong GA trigger, such as Consent Initialization- All Pages.

Read more details on how to check if Google Consent Mode v2 is implemented correctly, ant the right triggers are selected. 

 

Step 3. Check the default consent state

Before interacting with the cookie banner, check the default consent state.

In Europe, California, and other regions, where opt-in consent is required, the default consent state should usually be denied for relevant storage and advertising signals.

Check what consent signals you see. You should find the following signals:

  • ad_storage
  • analytics_storage
  • ad_user_data
  • ad_personalization

If these values are missing, Consent Mode v2 may not be fully installed.

If ad_user_data and ad_personalization signals are missing, you may still be using an older Consent Mode setup.

See the guide on how to update the GTM template to Consent Mode v2. 

 

Step 4. Interact with your cookie banner

Test your cookie banner signals by clicking “Reject all” and “Accept All” on the cookie banner.

In Tag Assistant, check whether the consent state corresponds to the user choice.

When you click the “Reject all” button, analytics, advertising, remarketing, and conversion tags should not fire.

Now click “Accept All” and check whether Tag Assistant shows updated consent values.

For example, accepting analytics cookies should update analytics_storage. Accepting marketing or advertising cookies should usually update ad_storage, ad_user_data, and ad_personalization.

Then test custom choices.

For example, accept analytics but reject marketing cookies, and check on GTM whether the signals match that choice.

If the consent state does not match the user’s selected categories, your CMP/GTM mapping is not working correctly.

 

Step 5. Check whether Google tags respect consent

After testing banner choices, review your Google tags in GTM Preview mode.

Check:

  • GA4 configuration tags.
  • GA4 event tags.
  • Google Ads conversion tags.
  • Google Ads remarketing tags.
  • Floodlight tags.
  • Custom HTML tags that load Google scripts.

 

Test with special care tags that fire before consent is known and tags that fire even when the required consent is denied.

If a tag is hardcoded directly on the website instead of being managed through GTM, it may bypass your GTM consent settings completely, so Google tags will not respect user consent choices.

 

Step 6. Test important user actions

Test user tracking on important user actions:

  • Page views
  • Form submissions
  • Button clicks
  • Purchases
  • Signups
  • Lead events
  • Google Ads conversions
  • GA4 events.

 

For each action, check the consent state when the tag fires to see timing issues. A tag may behave correctly on page load but fail later during a conversion event.

 

Step 7. Test different web pages

Testing Consent Mode behavior only on your homepage is not enough.

Test different templates and page types, including:

  • Landing pages built outside the main CMS.
  • Checkout pages using a separate platform.
  • Thank-you pages with hardcoded conversion scripts.
  • Subdomains.
  • Embedded forms.
  • Old page templates.

 

These are common places where Consent Mode v2 could not work.

 

Step 8. Confirm the setup in Google Tag Assistant

Finally, use Google Tag Assistant to verify the full Consent Mode implementation.

Tag Assistant can help show whether consent signals are present, whether they update after user action, and whether tags read consent in the right order.

Use Google Tag Assistant to make sure:

  • Default consent is set early.
  • All four Consent Mode v2 signals are present.
  • Consent is updated after the visitor makes a choice.
  • Google tags behave according to the consent state.
  • No major consent warnings appear.

Frequently Asked Questions

Why does consent stay denied after the user clicks “Accept all”?

This usually means your banner UI and Google consent state are not properly connected. Check the CMP/GTM integration and make sure consent updates are triggered after every banner action. Use CookieScript, a Google-certified CMP, to send the right consent signals to Google.

What are the most common setup problems for basic vs advanced consent mode?

The most common setup problem is mixing Basic and Advanced Consent Mode rules instead of choosing a single approach. In Basic Consent Mode, tags may stay blocked even after consent if the CMP does not send a proper update to GTM. In Advanced Consent Mode, the usual issue is timing: Google tags load before default consent is set, which can trigger consent warnings or lead to unreliable behavior.

Can Consent Mode v2 work without a CMP?

Yes, Consent Mode v2 can work without a third-party CMP, but only if you build and maintain your own consent banner and manually send the correct consent signals to Google. However, most websites use a CMP with Consent Mode v2 integration because it handles the banner, consent storage, regional rules, Google signal mapping, and updates consent states after user interaction. CookieScript is a Google-certified CMP with built-in Consent Mode v2.

Why is Consent Mode v2 missing ad_user_data?

ad_user_data is usually missing because the site is still using an old Consent Mode setup that only sends ad_storage and analytics_storage. Consent Mode v2 added two new consent states (ad_user_data and ad_personalization), with ad_user_data controlling whether user data can be sent to Google for advertising. See the guide for updating the GTM template to Consent Mode v2. 

Why are Consent Mode v2 signals missing?

Common causes include an outdated CMP, Consent Mode v2 not being enabled in the CMP settings, incorrect CMP-to-Google signal mapping, missing consent update events after the user’s choice, or Google tags firing before default consent is set. To fix it, update the CMP/GTM setup, set default consent before tags run, send consent updates after every banner action, and verify the result in Google Tag Assistant. se CookieScript, a Google-certified CMP, to implement Consent Mode v2 seamlessly.