Your insurance company cannot legally total your car without your permission. Totaling is when you've been in an accident and the repairs cost more than what it's worth.
In Texas, if you are dealing with an insurance company of an at fault party, they want to total your car, yet repairs are less that ACV, threaten to sue their clientin small claims, when you win they have to pay. Pay for repairs then bill them, it works!
If the car cannot be repaired to a safe working condition without exceeding the fair market value of the vehicle at the time of accident. Insurance companies may have a threshold above which a vehicle will be considered totaled (i.e. if the cost to repair exceeds 70% of value).
The insurance company will "total" your car when the cost to repair it is greater than the value of the car. Understand that it isn't the replacement cost that we're talking about, its the depreciated current value, adding in any verified upgrades you made. The exception is if you have a policy specifically written for the replacement cost.