Enhanced Conversions never sent hashed emails — 38% of conversions recovered

The situation

A UK skincare DTC brand had Google Enhanced Conversions enabled in their account settings for 4 months. Their Google Ads rep confirmed it was "active." Conversion volume had been declining month over month.

The problem

Enhanced Conversions was toggled on in Google Ads but the actual hashed email data was never being passed. The gtag snippet was firing with an empty enhanced_conversion_data object — no email, no phone, no address. Google had no additional match signal beyond click IDs, which had been eroding since cookie restrictions tightened.

What we did

1. Pulled GTM debug view and inspected the conversion tag — enhanced_conversion_data object was present but all fields were empty strings
2. Traced the data layer: Shopify checkout was storing customer email in checkout.email but the GTM variable was reading from customer.email — wrong key
3. Fixed the data layer variable mapping and verified SHA-256 hashing via the Google Tag diagnostic tool
4. Compared 30-day pre vs post — Google's match rate jumped from 34% to 71% within 2 weeks

Why it worked

Enhanced Conversions is often "enabled" at the account level but never actually implemented at the tag level. The field mapping from ecommerce data layer to the enhanced_conversion_data object requires a correct GTM variable setup. An empty object sends nothing — Google reports it as active because the tag fires, not because it contains data.