Possible claims, depending on facts
In some situations, yes. Renting out an unpermitted unit, especially one with serious defects, can expose a landlord to legal claims — and tenants of illegal units sometimes have more options than they expect.
Depending on the facts, possible claims can include habitability claims for serious unrepaired conditions, claims related to being displaced from an unlawful unit, and in some cases efforts to recover rent paid for an illegal home. If the landlord concealed the unit's status or used illegal "self-help" tactics to push you out, that can add to the picture. Where a dangerous condition in the unit caused injury, an injury claim may also be possible.
What claims fit depends heavily on the specifics — how the unit was illegal, its condition, what the landlord knew, what harm resulted, and local law. Good records of your lease, payments, conditions, and communications make a real difference.
Because these cases can be complex and fact-specific, professional guidance matters. A free, confidential review can look at your situation and explain what options, if any, may be available to you.
This is general information about California tenant rights, not legal advice. Every situation is different.