Can my landlord shut off utilities or change the locks instead of filing an eviction?

No, never, regardless of how much rent is owed or how clearly you're behind. California calls this a "self-help eviction," and it's flatly illegal, full stop, no exceptions for a landlord who's frustrated with the process.

Beyond being unlawful, it comes with its own statutory penalties layered on top of whatever happens in the eviction case itself. If this is happening to you right now, treat it as its own urgent, separate issue, worth acting on immediately rather than folding it quietly into your eviction defense.