Full Answer

The gcs parameter is a single string embedded in every Google Analytics and Google Ads network request. It encodes the real-time consent state your Consent Management Platform is passing to Google tags. G1 at the start means the consent API loaded; the three digits that follow represent ad_storage, analytics_storage, and ad_user_data respectively, where 0 is denied and 1 is granted. A fully consented hit reads G111; a fully denied hit reads G100. Any other combination — G110, G101 — tells you exactly which consent type is misconfigured.

The audit takes under five minutes. Load your site in an incognito window, open DevTools (F12), switch to Network, and type collect into the filter. Decline the cookie banner and confirm you see gcs=G100. Then accept and reload — gcs should flip to G111. If it does not update, your CMP is failing to push the consent state change to the Google consent API, and every conversion after that click is lost from your reports.

This matters because 25% of Consent Mode setups currently contain this exact class of error — tags fire before consent updates, or consent updates never propagate. For the full five-minute walkthrough, see [25% of Consent Mode Setups Are Broken — The Five-Minute WooCommerce Audit That Finds Yours](https://seresa.io/blog/cookie-consent-tracking-data-loss/25-of-consent-mode-setups-are-broken-the-woocommerce-audit-that-finds-yours).