California law tends to be distinctive, yes

Knute is right that diminished value is a classic element of tort damages. But there may also be rules that cap damages in a way that limits your recovery, or the insurance company may be willing to tell you to make their day on that, because it's harder to prove than repair cost.

For example, in Tennessee, diminished value in this context is recoverable as a general matter, but your total recovery for property damage can't exceed the difference between the value of the vehicle immediately before the wreck and its value immediately after the wreck (i.e., before the repair). As a practical matter that hampers lost-value recoveries.

But what the rule on this in California I haven't a clue. You could tell me almost anything and I would believe it.