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Google Consent Mode Diagnostics FAQs

Version: 1.1

Last Updated: June 9, 2026

 

This FAQ provides troubleshooting guidance for common Google Consent Mode (GCM) warnings and errors detected by the scan. Each entry includes the warning/error message, type, and actionable steps for support teams.

NOTE: Automated alerts will be sent each month for the websites included in the scan if any issues with consent mode are detected.
 

Troubleshooting Common Errors and Warnings 

 

Troubleshooting Common Errors and Warnings

Tags are firing before consent is initialized

Type: Error

Explanation: This means tags (such as analytics or marketing scripts) are loading before the user’s consent choices are set, which can lead to non-compliance. A common cause is Google Tag Gateway for advertisers (GTG), which serves Google tags through your own first-party domain via your CDN or server. When GTG is enabled through one-click CDN injection (for example, via Cloudflare), the CDN injects the Google tag into the page, which often prevents you from controlling the script load order — so the tag can fire before the TrustArc Cookie Consent Manager has set the default consent values.

Troubleshooting:

  • Ensure Consent Mode is initialized before any tags are loaded on the page.
  • Check the order of script execution in your site's source code.
  • Use browser developer tools to verify that consent initialization occurs before tag firing.
  • Check whether your tag is enrolled in Google Tag Gateway (see “How to Check” below). If it is, follow the GTG guidance in the next section.

If your tag is enrolled in Google Tag Gateway (GTG):

If this error appears and your tag is enrolled in GTG, the late consent signal is likely caused by the GTG load order. Choose one of the following remediation paths:

  • Recommended: Adopt advanced consent mode (U+C) and enable Data Transmission Controls and Global Consent Defaults according to your needs. Advanced consent mode is the recommended mechanism for GTG-enabled tags because it is compatible with manual GTG setups: Google tags load with denied consent defaults and adjust their behavior based on the user’s consent state, so a GTG-served tag that loads early does not collect data as if consent had been granted.
  • Migrate all tags into a single Google Tag Manager (GTM) container and deploy GTM via Google Tag Gateway, so consent initialization is managed inside the container.
  • Set up Google Tag Gateway manually (instead of one-click CDN injection) so that you control the script import order, and load the TrustArc Cookie Consent Manager script and Consent Mode default command before the Google tag.

Note that blocking-based (basic) implementations cannot be guaranteed when the tag is injected by the CDN, which is why advanced consent mode is the more reliable approach for GTG.

How to Check:

  • Inspect the network requests and console logs for tag firing events before consent initialization.
  • Confirm that the Consent Mode script is loaded and executed first.
  • Check GTG enrollment: in Google Tag Manager or your Google tag settings, open the Google tag gateway section — an “Active” status appears next to each website domain where GTG is running.
  • Use Google Tag Assistant: connect to your website URL, then under Summary > Output > Hits Sent, check whether hits are routed through your own measurement path (your domain) rather than a Google domain. GTG-served tags load from your own domain instead of googletagmanager.com.
  • Re-run the Google Consent Mode diagnostics scan after remediation to confirm the error is resolved.

Learn more:

Consent Mode is enabled, but no developer ID is set

Type: Warning

Explanation: Consent Mode is active, but the required developer ID is missing, which may prevent proper tracking and reporting.

Troubleshooting:

  • Verify your Google Tag Manager (GTM) or GTag configuration for the developer ID parameter.
  • Ensure that you are using the scripts or GTM Template provided by TrustArc for proper integration.

How to Check:

  • Review the Consent Mode initialization code for the developer ID.
  • Use browser dev tools to inspect the configuration object.
  • Confirm only dNTIxZG is present.
     

Not using Consent Mode with TrustArc’s recommended GTM Template or GTag

Type: Warning

Explanation: The scan detected Consent Mode, but not with TrustArc’s recommended GTM Template or GTag, which may reduce integration quality.

Troubleshooting:

  • Consider switching to TrustArc’s GTM Template for better integration.
  • Review your current Consent Mode implementation and compare with TrustArc’s recommended setup.

How to Check:

  • Check if the GTM Template or GTag is present in your configuration.
  • Review the scan results for template usage flags.
     

GTag function is not defined

Type: Warning

Explanation: The GTag function is missing, so Consent Mode cannot communicate with Google services as expected.

Troubleshooting:

  • Ensure the GTag function is initialized if using Consent Mode via JavaScript.
  • Add the GTag script to your site if it is missing.

How to Check:

  • Open the browser console and type typeof gtag to verify it is a function.
  • Check for GTag script in the page source.
     

Consent Mode is not using TrustArc’s GTM Template

Type: Warning

Explanation: Consent Mode is detected, but not using TrustArc’s GTM Template, which may limit advanced features and support.

Troubleshooting:

  • Consider using TrustArc’s GTM Template for enhanced integration.
  • Update your GTM configuration to use the template.

How to Check:

  • Review GTM container setup for TrustArc template usage.
  • Check scan results for template flags.
     

Consent is being managed using GTag

Type: Info

Explanation: Consent management is handled via GTag, which works but may lack some TrustArc template benefits.

Troubleshooting:

  • Consider upgrading to TrustArc’s GTM Template for streamlined consent management.
  • Evaluate current GTag setup for compatibility.

How to Check:

  • Inspect scan results for GTag usage.
  • Review your site’s consent management scripts.
     

Consent Mode GTag and Template detected

Type: Warning

Explanation: Both GTag and GTM Template are present, which can cause conflicts or duplicate consent handling.

Troubleshooting:

  • Avoid using both GTag (JavaScript) and GTM Template together.
  • Choose one method for consent management.

How to Check:

  • Review scan results for both GTag and template flags.
  • Inspect your GTM and GTag configuration.
     

Consent Mode default is not set

Type: Error

Explanation: No default consent values are set, so tags may fire without proper user consent.

Troubleshooting:

  • Set default consent values in your Consent Mode configuration.
  • Ensure defaults are defined before any tags fire.

How to Check:

  • Use GTM container preview mode to verify default consent values are set correctly.
  • Inspect the Consent Mode initialization code for default values.
  • Review scan results for default consent flags.
     

Consent Mode update is not set

Type: Error

Explanation: Consent values are not updated after user interaction, risking inaccurate consent records.

Troubleshooting:

  • Use GTM container preview mode to verify default consent values are set correctly.
  • Ensure consent values are updated based on user interactions.
  • Implement update logic in your Consent Mode setup.

How to Check:

  • Review event handlers for consent updates.
  • Check scan results for update consent flags.
     

dataLayer is not defined

Type: Warning

Explanation: The dataLayer object is missing, which is required for GTM and Consent Mode to function properly.

Troubleshooting:

  • Initialize the dataLayer before firing any tags.
  • Add window.dataLayer = window.dataLayer || []; at the top of your scripts.

How to Check:

  • This is required when using the JavaScript implementation.
  • Open browser console and type typeof window.dataLayer.
  • Check for dataLayer initialization in your code.
     

No consent events detected in dataLayer

Type: Warning

Explanation: No consent events are being pushed to the dataLayer, so GTM cannot react to consent changes.

Troubleshooting:

  • Push consent events to the dataLayer as required by Consent Mode.
  • Review your GTM setup for consent event triggers.

How to Check:

  • Inspect the dataLayer contents in the browser console.
  • Review scan results for consent event detection.
     

Consent type <key> is not set

Type: Warning

Explanation: At least one required consent type is missing from the configuration, which may lead to incomplete consent management.

Troubleshooting:

  • Ensure each consent type is configured in Google Consent Mode.
  • Update your configuration to set all required consent types.

How to Check:

  • Review scan results for missing consent types.
  • Inspect Consent Mode configuration for completeness.
     

Default consent is undefined for: <types>

Type: Warning

Explanation: Some consent types do not have default values, which can cause tags to fire without user consent for those types.

Troubleshooting:

  • Set default consent for all listed types in your configuration.
  • Review and update Consent Mode setup as needed.

How to Check:

  • Inspect scan results for undefined default consent types.
  • Check Consent Mode initialization code.
     

Collect events were detected, but consent state did not change

Type: Warning

Explanation: Collect events occurred, but the user’s consent state did not update after processing the acceptAll/rejectAll action, which may indicate a configuration issue or that consent was already granted.

Troubleshooting:

  • Verify Accept All/Reject All functionality updates consent state.
  • Ensure Tag Manager configuration aligns with expected consent flow.

How to Check:

  • Review scan results for collect events and consent state changes.
  • Test Accept All/Reject All actions on your site.
     

No collect events detected after the acceptAll/rejectAll action

Type: Warning

Explanation: No collect events were triggered after consent actions, which may mean the consent flow is not working as intended.

Troubleshooting:

  • Ensure Accept All/Reject All triggers collect events.
  • Verify Tag Manager configuration for correct event firing.

How to Check:

  • Inspect scan results for collect event detection.
  • Test consent actions and monitor network requests.
     

Consent Mode not detected

Type: Error

Explanation: Consent Mode scripts are missing, so user consent is not being managed according to Google requirements.

Troubleshooting:

  • Implement Consent Mode to manage user consents.
  • Add Consent Mode scripts to your site.

How to Check:

  • Review scan results for Consent Mode detection.
  • Inspect your site’s source code for Consent Mode scripts.
     

GCM parameters (gcd or gcs) detected, but Consent Mode is misconfigured

Type: Warning

Explanation: Google Consent Mode parameters are present in network requests, but the configuration is incomplete or incorrect.

Troubleshooting:

  • Ensure Google Consent Mode is correctly implemented and configured.
  • Activate Consent Mode to avoid data loss in Google Analytics.

How to Check:

  • Inspect network requests for gcd/gcs parameters.
  • Review Consent Mode configuration and scan results.
     

TrustArc Event Listener for GCM is not loaded

Type: Error

Explanation: The TrustArc Event Listener script is missing, so events for Google Consent Mode are not being handled by TrustArc.

Troubleshooting:

  • Implement and initialize the TrustArc Event Listener for Google Consent Mode.
  • Add the required event listener script to your site.

How to Check:

  • Inspect scan results for event listener detection.
  • Review your site’s scripts for the event listener.
     

Google Tag Manager (GTM) might not be loading on the page

Type: Warning

Explanation: GTM script is not detected, which may prevent tags and Consent Mode from working correctly.

Troubleshooting:

  • Verify GTM is installed and running.
  • Check for GTM script in your site’s source code.

How to Check:

  • Inspect scan results for GTM detection.
  • Use browser dev tools to check for GTM script loading.