Google Consent Mode vs IAB TCF v2.2 reference card

What this is

Google Consent Mode and the IAB Europe Transparency and Consent Framework (TCF) v2.2 are two distinct consent-signalling systems: Consent Mode governs whether and how Google’s own tags collect and use data (via granted/denied signals), while TCF governs vendor-level transparency and legal basis through a Consent Management Platform (CMP), the Global Vendor List (GVL), and the TC String. This card states which to run, maps every TCF purpose to its Consent Mode effect, and lists the timeouts, ad-serving requirements, and Additional Consent format an implementer needs at the point of integration.

The two systems at a glance

Google recommends implementing only ONE of the two, not both, to avoid unintended interactions. When signals conflict, Google takes the most conservative (most privacy-preserving) union of the signals.

The seven Consent Mode signals

Every signal takes granted or denied. The four advertising/analytics types above the divider (ad_storage, ad_user_data, ad_personalization, analytics_storage) are the ones these sources detail; the remaining three are named in the seven-type list but not further described in these sources.

Default vs update, basic vs advanced

Consent transmitted to Google (HTTP params)

The specific gcs/gcd value tables are widely reported by practitioners but are not published on the official Google page cited here. Treat community decodings as hints and confirm the values against the actual network requests your tags send.

TCF v2.2 taxonomy

Purposes and legal basis

Consent-only purposes (legitimate interest not permitted): 1, 3, 4, 5, 6. Consent-or-LI purposes: 2, 7, 8, 9, 10, 11.

Special Features and Special Purposes

How Google is registered under TCF

The two Google pages list a slightly different flexible/LI-default set (Ad Manager: 2, 7, 9, 10; Google Ads: 2, 5, 6, 7, 9, 10). The difference likely reflects product scope and is not reconciled explicitly in the docs. In both cases: Google will not work via TCF if the TC String indicates personalization (Purposes 3 and/or 4) is permitted under legitimate interest, and Google interoperates with Special Features 1 and 2 only when appropriate disclosure is provided and users opt in.

TCF to Consent Mode mapping

Google reads the TC String via the CMP and maps denied TCF purposes to Consent Mode signals:

The docs describe mapping only to the ad-related signals (ad_storage, ad_user_data, ad_personalization); deriving analytics_storage from the TC String is not described in these sources.

Ad-serving requirements via TCF (publisher)

Separately, recording a Google Ads conversion through the TCF integration requires Purposes 7, 9 and 10 (satisfied by consent or legitimate interest, since Google is flexibly registered for them). Without them, Google Ads will not record the conversion.

Enabling TCF in Google tags

Additional Consent (AC)

Certification, tags, and deadlines

Gotchas

1. Personalized ads or conversions silently stop while the banner looks fine → the CMP did not return a valid TC String within Google’s 500ms window, or returned error/stub/loading, so the tag fell back to defaults → load the CMP before Google tags and verify TCData status via the __tcfapi callback before relying on personalization.
2. TCF and Consent Mode both set, behavior is unpredictable or double-restricts → both integrations were implemented at once, and Google resolves conflicts by taking the most conservative union → choose one path: enable gtag_enable_tcf_support OR set Consent Mode signals directly, not both.
3. Personalized ads disabled despite many granted purposes → Purpose 1 consent is missing, so only Limited ads can serve regardless of other grants → capture explicit consent (not LI) for Purposes 1, 3 and 4.
4. Personalization stays off even with LI configured for it → Google refuses TCF integration when the TC String signals legitimate interest for Purposes 3/4, and v2.2 removed LI as a legal basis for Purposes 3 to 6 → configure the CMP to request consent, not LI, for Purposes 3 and 4.
5. A Google ad partner gets no consent though the banner was accepted → that vendor is an ATP not on the IAB GVL, so its consent lives in the Additional Consent string, not the TC String → use a Google-certified CMP that emits the ACv2 string and keep the ATP CSV in sync.
6. Remarketing and conversion measurement for new EEA users stop growing after early 2024 → Consent Mode v2 signals ad_user_data and ad_personalization are not being passed → upgrade to Consent Mode v2 and pass both, in addition to ad_storage and analytics_storage, via a certified CMP.
7. Conversions from EEA traffic are not recorded via TCF → Google Ads requires Purposes 7, 9 and 10 for conversion recording, and the CMP omits or restricts them → allow Purposes 7, 9, 10 (consent or LI) in the CMP configuration.

Quick recipes

<!-- Website-level enable: MUST run before the Google tag / GTM container. -->
<script>
  window['gtag_enable_tcf_support'] = true;
</script>
<!-- ...your Google tag (gtag.js) or GTM snippet loads AFTER this line... -->

// Alternative to gtag_enable_tcf_support: enable at the CMP level instead.
// The CMP sets this on the TCData it exposes to Google tags.
TCData.enableAdvertiserConsentMode = true;

// The OTHER integration path. Do NOT combine with gtag_enable_tcf_support.
// Denied-by-default state, set before any Google tag fires:
gtag('consent', 'default', {
  ad_storage: 'denied',
  ad_user_data: 'denied',
  ad_personalization: 'denied',
  analytics_storage: 'denied',
});
// Then update after the user interacts with the banner:
gtag('consent', 'update', {
  ad_storage: 'granted',
  ad_user_data: 'granted',
  ad_personalization: 'granted',
  analytics_storage: 'granted',
});

// ACv2 format: 2~[consented ATP IDs]~dv.[disclosed ATP IDs]
// Only a TCF-registered CMP may actually mint this; shown here for parsing/QA.
function buildAcV2(consented, disclosed) {
  const c = consented.join('.');                          // e.g. "1.35.41.101"
  const d = disclosed.length ? 'dv.' + disclosed.join('.') : 'dv';
  return `2~${c}~${d}`;
}
buildAcV2([1, 35, 41, 101], []);  // "2~1.35.41.101~dv"
buildAcV2([1, 10], [2, 3, 4]);    // "2~1.10~dv.2.3.4"
buildAcV2([], [1, 2, 3, 4, 10]);  // "2~~dv.1.2.3.4.10"

// If the CMP does not return valid data within 500ms, or reports
// 'error' / 'stub' / 'loading', Google tags fall back to DEFAULT consent.
// Confirm the CMP is ready before relying on personalization.
// (__tcfapi signature: see the TCF v2.2 quick reference.)
const TIMEOUT_MS = 500;
let settled = false;
const timer = setTimeout(function () {
  if (!settled) console.warn('CMP not ready in 500ms -> Google uses defaults');
}, TIMEOUT_MS);

window.__tcfapi('addEventListener', 2, function (tcData, success) {
  const notReady = ['error', 'stub', 'loading'];
  if (success && notReady.indexOf(tcData.cmpStatus) === -1) {
    settled = true;
    clearTimeout(timer);
    // tcData is trustworthy here; safe to gate personalization on it.
  }
});

# Tagless (server-to-server) ad requests must carry the IAB signals manually.
# gdpr = 0 (does not apply) or 1 (applies); gdpr_consent = the TC String.
https://securepubads.g.doubleclick.net/gampad/ads?...&gdpr=1&gdpr_consent=CPqABCD...ByxAAA
# If an NPA signal AND a TC String are both present, Google applies the most
# conservative setting.

Related

• Hub: Privacy and consent guides
• Consent Mode v2 reference · IAB TCF v2.2 implementer quick reference

Sources

Official pages these values were read from (read 2026-07-20):

• Consent mode concepts — Tag Platform, Google for Developers (read 2026-07-20)
• Implement the Transparency and Consent Framework (TCF strings) — Tag Platform (read 2026-07-20)
• Google’s Additional Consent technical specification — Ad Manager Help (read 2026-07-20)
• Interoperability guidance for vendors working with Google via the IAB Europe TCF — Ad Manager Help (read 2026-07-20)
• Publisher integration with the IAB Europe TCF — Ad Manager Help (read 2026-07-20)
• Google consent management requirements for the EEA, UK, and Switzerland — Ad Manager Help (read 2026-07-20)
• Google Ads integration with the IAB TCF — Google Ads Help (read 2026-07-20)
• Consent mode reference — Google Ads Help (read 2026-07-20)
• Transparency and Consent Framework — IAB Europe (read 2026-07-20)
• Summary of Purposes/Features, IAB TCF v2.2 — Didomi (secondary mirror of the IAB list) (read 2026-07-20)

Honesty notes. The gcs/gcd request-parameter encodings are not published on the Google page cited here; treat community value tables as hints. The flexible/LI-default purpose set differs between the Ad Manager guidance (2, 7, 9, 10) and the Google Ads page (2, 5, 6, 7, 9, 10) and is not reconciled in the docs. The docs describe TCF-to-Consent-Mode mapping only for ad-related signals, not analytics_storage. TCF v2.2 purpose and feature names were confirmed via Didomi’s summary as a mirror because the IAB Europe FAQ PDF did not parse as text; the authoritative machine-readable source is the GVL JSON at vendor-list.consensu.org. The specific advertiser-side Consent Mode v2 enforcement date sometimes cited as March 2024 comes from secondary sources; the official pages cited here document publisher certified-CMP/TCF deadlines instead.