Struggling Google Ads accounts rarely have a bidding problem. In our experience working across accounts from early-stage businesses to mid-market firms spending six figures a month, the underlying issue is almost always the same: the account is optimising toward the wrong signal, or toward no signal at all.

Smart Bidding — Target CPA, Target ROAS, Maximise Conversions — is powerful automation. But it is only as powerful as the conversion data you feed it. When conversion tracking breaks, the algorithm does not stop bidding; it continues spending, guided by ghost data or silence. Identifying and fixing the tracking layer is not a preliminary step before the real work. It is the real work.

Here are the five ways Google Ads conversion tracking breaks in practice, how to diagnose each, and how to fix them.

Since Google’s EU User Consent Policy became mandatory for EEA traffic, consent mode is a requirement — not an enhancement. When it is misconfigured, the tag either fails to fire at all for users who decline, or fires but sends unmodelled data that Google cannot use reliably.

Diagnosis: In Google Ads, go to Tools → Conversions. Look for conversion actions showing far lower volumes than you would expect given traffic levels, or actions tagged as “Consent mode: basic” when you intended “advanced.” Cross-reference with your CMP (consent management platform) — confirm the consent signal is actually passing to the tag layer.

Fix: Implement consent mode v2 correctly, with both ad_storage and ad_personalization parameters. Verify via Tag Assistant that the tag fires with the correct consent state. If using Google Tag Manager, confirm the consent initialisation trigger runs before any conversion tags.

2. gtag misfires — tag fires on the wrong page or not at all

The conversion tag fires once, on the confirmation or thank-you page, after the desired action has been completed. Tags placed on the wrong page — the contact form itself rather than the submission confirmation, a category page rather than a product receipt — misattribute or miss conversions entirely.

Diagnosis: Use Tag Assistant in Google Ads (Tools → Tag Assistant) or the Chrome Tag Assistant extension. Navigate through your conversion flow manually and confirm the tag fires exactly once on the right page. If you are using GTM, check the trigger conditions carefully — “All Pages” triggers are a common culprit.

Fix: Verify the trigger is scoped to the confirmation URL or a custom event (e.g., form_submit_success) that only fires on true completion. If using a CRM-side thank-you redirect, confirm the redirect destination is tagged.

3. Flat or missing conversion values

This is the step most accounts skip entirely. By default, many Google Ads accounts assign every conversion a flat value of £1, or no value at all. The result: Smart Bidding treats a high-intent £20,000 sales enquiry the same as a newsletter signup. The algorithm optimises for volume, not value.

Diagnosis: In Tools → Conversions, inspect the “Conv. value” column across your conversion actions. If every action shows the same value (or £0), your bidding model cannot differentiate between leads.

Fix: Assign real values to your conversion actions — even rough estimates are better than nothing. For lead generation, this means researching your close rate and average deal value, then assigning a proportional lead value. A business with a 10% close rate and £5,000 average deal value has leads worth approximately £500 each.

This is the foundation of value-based bidding: telling Google what a conversion is actually worth in commercial terms, so Target ROAS bidding can optimise toward revenue, not just volume. It is one of the highest-leverage changes available to an account that is already spending at scale. If you want to understand how this fits into a broader account health review, our Google Ads audit framework covers the full diagnostic sequence.

4. Duplicate or missing conversion actions

Duplicate conversion actions — created during platform migrations, A/B test setups, or agency onboarding — overcount conversions and distort the data Smart Bidding uses to set bids. Missing conversion actions, where the action has been paused or deleted without a replacement, leave the account blind.

Diagnosis: In Tools → Conversions, look for duplicate conversion names (e.g., “Contact Form” and “Contact Form - Old”), actions marked as “Inactive,” and the “Include in Conversions” toggle. Any action set to “Include: Yes” that is inactive or duplicated is polluting your bidding signal.

Fix: Audit every conversion action. Archive or remove superseded actions. Confirm exactly one active primary conversion action exists per meaningful goal. Set secondary actions (e.g., page views, session duration thresholds) to “Include: No” so they inform reporting without distorting Smart Bidding.

5. GA4-import gaps and broken connections

Importing conversions from GA4 is convenient, but GA4 is a live system that changes. When someone renames a key event in GA4, removes the conversion toggle, or migrates to a new GA4 property, the Google Ads import silently fails — and the account continues bidding on stale or empty data.

Diagnosis: In Google Ads, go to Tools → Linked accounts → Google Analytics. Confirm the linked GA4 property is active and the correct property. Then in GA4, confirm the key events you are importing are still marked as conversions and have not been renamed or moved to a different data stream.

Fix: After any changes to GA4 — property settings, event names, data streams — audit the Google Ads import. Re-link if necessary. If the import has been broken for more than a few days, Google’s Smart Bidding model will need time to recalibrate once clean data begins flowing again.

Conversion tracking is not a one-time setup. It is infrastructure that requires the same maintenance as any other critical system — particularly when consent requirements, tag managers, CRMs, and GA4 are all in the mix.

If you want a structured assessment of where your account currently stands, our AI Paid-Ads Audit includes a full conversion-tracking review as part of the diagnostic. You can also use our Account Health Scorecard to get an initial read on tracking health, wasted spend, and bidding strategy fit — before committing to a full engagement.