Early in May 2025, Google shifted the format of GA4’s session-related cookies from the familiar GS1 to a new GS2 format with no formal announcement. If you’re heavily reliant on Google Analytics 4 (GA4) cookies, this change could impact how you track your valuable customer data.
You might be thinking, “What does a cookie format change have to do with my campaigns?” Well, if your current systems, data pipelines, CRM integrations, attribution models, or even your server-side tagging setups are built to parse the older GA cookie format, this silent update could be throwing a wrench in your works. Suddenly, your meticulously crafted data flows might experience disruptions, leading to inaccurate insights and potentially misinformed marketing decisions. In our industry, where every lead and every piece of customer behavior data counts, that’s not a risk we can afford to take.
You might have a fantastic new campaign rolling out, driving tons of traffic to your website. You’re eager to see how users are engaging, where they’re coming from, and ultimately, which touchpoints are leading to conversions. But if your systems can’t properly interpret the new cookie format, you could be looking at incomplete or even broken attribution data. The result is you might not accurately understand the true performance of your campaigns, making it harder to optimize your spend and prove your ROI.
The good news is that agile agencies, like Chumney & Associates, are already on top of this. We’ve updated our systems to correctly interpret both the new GS2 format and intelligently fall back to the older GS1 formats where needed. This proactive approach ensures that our partners and clients don’t experience any disruption to their crucial attribution or offline event tracking. It’s a prime example of how staying ahead of these technical shifts can safeguard data integrity.
It’s worth noting that the original _ga cookie, which stores the Client ID (a super important piece of the puzzle for user ID stitching in CRMs and other backend systems), remains unchanged. This is a small mercy, as it means a core component for linking online behavior to offline customer profiles is still stable.
However, this recent change serves as a powerful reminder for all of us in the automotive marketing space. It’s time to audit your cookie dependencies. Are you unknowingly relying on raw GA cookie formats for critical operations? If so, it’s a good idea to review your server-side tagging strategies and consider how you can make your data collection more resilient to future, unannounced changes from Google.
The landscape of digital marketing is constantly evolving, but Chumney & Associates can help you adapt and stay informed to drive continued success for your dealership or automotive brand. Don’t let a silent cookie update throw your marketing engine off track. Chumney & Associates today and let’s work together.
