If you run Google Ads or use Google Analytics 4 on a website with visitors in Ireland or anywhere in the EU, Consent Mode v2 is not optional any more. Without it, Google limits what you can measure and who you can advertise to.
When we audit Irish business websites, a broken consent setup is one of the most common problems we find. This guide explains what Consent Mode v2 is, how we set it up, and the mistakes to look out for.
What is Consent Mode v2?
Consent Mode is Google’s way of letting your cookie banner talk to Google’s tags. When a visitor accepts or rejects cookies, the banner sends that choice to GA4, Google Ads and other Google tags, and they change how they behave.
Version 2 added two new signals. There are now four you need to know:
- ad_storage: can cookies be stored for advertising?
- analytics_storage: can cookies be stored for analytics, such as GA4?
- ad_user_data: can the visitor’s data be sent to Google for advertising?
- ad_personalization: can the data be used for personalised ads, such as remarketing?
The first two control whether data is collected. The two newer ones control how Google can use that data for ads.
Why it became required
Under the EU’s Digital Markets Act, Google was designated a gatekeeper and had to tighten how it gets consent for ads. From March 2024, Google began requiring Consent Mode v2 signals for traffic from the European Economic Area and the UK.
In practice, if those signals are missing, you lose access to features many advertisers rely on:
- Building remarketing and audience lists
- Personalised advertising to those audiences
- Full conversion measurement, including enhanced conversions
For a business spending on Google Ads, that means less data to optimise with and weaker campaigns.
Basic vs advanced mode
There are two ways to run Consent Mode, and the difference matters.
Basic mode
Google tags are blocked completely until the visitor gives consent. If they reject, nothing is sent to Google at all. This is the simpler and more cautious option.
Advanced mode
Google tags load straight away with consent set to denied. If the visitor rejects, the tags send limited, cookieless pings with no identifiers. Google uses those pings to model the conversions and behaviour you would otherwise miss.
Advanced mode gives you better modelled data, but it does send some information before consent. Talk to whoever handles your data protection before choosing it. Many smaller Irish businesses are well served by basic mode.
How we set up GA4 with Consent Mode v2
Here is the order we follow on client sites.
1. Choose a proper consent banner
Use a consent management platform (CMP) that supports Consent Mode v2. Google keeps a list of certified providers through its CMP Partner Program, and those are the ones we recommend. A free plugin that only shows a message, without controlling tags, is not enough.
The banner should offer accept and reject with equal weight, and let people manage categories. Our guide to website cookies covers what the Irish rules expect from a banner.
2. Install everything through Google Tag Manager
We put GA4, Google Ads and any other tags into Google Tag Manager (GTM) rather than pasting code into the theme. That gives us one place to control what fires and when.
The CMP sets the default consent state (everything denied) on the Consent Initialisation trigger, before any other tag runs. When the visitor makes a choice, the CMP sends an update.
3. Set consent checks on each tag
Google’s own tags read Consent Mode automatically. Other tags, such as the Meta Pixel or LinkedIn, do not. For those, we use GTM’s consent settings so they only fire when the right category has been accepted.
4. Mark the events that matter
GA4 now calls conversions “key events”. Decide what counts as a lead or sale for your business, such as a form submission, a booking, a phone click or a purchase, and mark those as key events. Then import them into Google Ads where relevant.
A GA4 property with no key events tells you about traffic but not about business results.
5. Test with Tag Assistant
We use Tag Assistant and GTM preview mode to check the consent state on page load, after accept and after reject. We confirm that:
- All four signals start as denied
- They update correctly when the visitor accepts
- Non Google tags stay silent after a rejection
- Key events fire once, with the right details
Common mistakes we find
These come up again and again in our tracking audits, including on projects like Fastmoves, where conversion tracking was a core part of the work.
A banner that does not block anything
The banner looks fine, but tags fire regardless of what the visitor clicks. This is the most serious problem, because it gives a false sense of compliance.
GA4 firing before consent
Often GA4 has been added twice: once in GTM and once by a plugin or the theme. The plugin version ignores the banner entirely.
No conversions marked
GA4 is collecting page views, but nothing is set as a key event. Google Ads then has no reliable signal to optimise towards.
Duplicate tags
Two GA4 tags or two Google Ads conversion tags on the same page double count results. Reports look great, and the numbers are wrong.
Missing the two new signals
Older setups only send ad_storage and analytics_storage. Google copies ad_storage across to ad_user_data for some of these, but ad_personalization is not mapped, so remarketing and personalised ads for EEA traffic need a proper upgrade to v2.
Where to start
Open your site in a private window and use Tag Assistant to see what fires before you click anything on the banner. If GA4 or ad tags appear straight away in basic mode, something needs fixing.
If you would like a second pair of eyes, book a free 15 minute call and we will check your setup with you. For the bigger picture on why GA4 matters, read GA4 vs the Meta Pixel.
This is general guidance, not legal advice.
FAQ
Do I need Consent Mode v2 if I do not run Google Ads?
It is still worth having. GA4 respects the consent signals, and if you start running ads later, the setup is already in place.
Is a Consent Mode v2 banner the same as being GDPR compliant?
No. Consent Mode passes choices to Google. You still need a banner that meets Irish and EU consent rules and a clear cookie policy.
How long does a proper setup take?
For a typical business site, it is usually a short job. Sites with lots of tags, ecommerce or several ad platforms take longer to test properly.
Sources and further reading
- Consent mode overview, Google for Developers
- Verify and update consent settings in Google Analytics, Google Analytics Help
- EU user consent policy, Google
- Commission designates six gatekeepers under the Digital Markets Act, European Commission
- Consent Mode CMP partners, Google
- Tag Manager consent mode support, Tag Manager Help
- Mapping ad_storage to ad_user_data, Tag Manager Help
- Conversions and key events, Google Analytics Help
- Troubleshoot consent mode with Tag Assistant, Google for Developers