Smog Check Prep in San Francisco: How to Avoid a Retest

Local driving, simple maintenance, and what we see in the bay.

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North Beach · San Francisco · Auto Repair

Nobody loves smog day. The trick is to make it boring—in a good way. A little prep the week before keeps you out of the retest line and saves a Saturday.

North Beach · San Francisco · Auto Repair

Warm the engine fully

Fix CEL and pending codes

Battery disconnect resets monitors

Drive cycle basics

Short trips leave emission monitors incomplete. Take a longer highway drive before testing.

Any check engine light (even pending) can fail a smog. We’ll scan and advise next steps.

If your battery was disconnected recently, readiness monitors may reset—give it a few drive cycles.

We can help perform a simple drive cycle and verify monitors are set.

Need help now?

Our go‑to checklist

Warm it up: a good 20–30 minute mixed drive (Embarcadero + a bit of 280/101) sets monitors and evaporates moisture.

Scan first: we’ll check for pending codes and readiness before you pay a test station.

No recent battery disconnects: if you had work done, drive a couple cycles so monitors complete.

If you did have a repair

We’ll take it for a short drive cycle and verify monitors are green. Once they are, you’re good to roll into the STAR station without surprises.

Local tip

Top off with Top Tier fuel mid‑week, and if you’re borderline on maintenance, a fresh air filter can help your numbers.

Written by the Bob’s Auto SF crew on Columbus Ave — real stories from the bay, steep streets and all.

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