Smog is emissions only
The California smog check is an emissions inspection. It examines the engine management system, the exhaust and the evaporative system. It does not inspect glass, tyres, brakes or lights.
So a cracked windshield does not fail a smog check and does not block registration renewal on its own.
The citation is a separate mechanism
California Vehicle Code section 26710 requires the windshield to be in a condition that does not impair the driver's vision. There is no published maximum crack length — enforcement turns on whether the damage sits in the driver's field of view.
It is normally written as a correctable "fix-it" ticket: repair or replace it, get the correction signed off, pay a dismissal fee, and it clears.
Where they intersect
If you accumulate a correctable citation and do not clear it, that can eventually become a hold — not through the smog process, but through the citation itself going to failure-to-appear.
The practical version: fix the glass because you cannot see properly out of it, not because of the smog check.
Need this done rather than explained? There is no shop to drive to. We come to wherever your car already is — your driveway, your workplace car park, an apartment lot, or the side of the road it stopped on — anywhere in greater Sacramento, with no call-out fee and no mileage charge. Give us the year, make and model and you will have a firm price before the call ends.