In the vast majority of cases, filing a DFEH/EEOC complaint against your employer is a pure formality, as these agencies close their file and issue a right to sue letter to the complainant in over 95% of the cases. DFEH and EEOC only choose a few, particularly egregious cases to pursue every year due to lack of resources and the number of discrimination complaints they receive. Otherwise, a typical DFEH investigation ends up with a letter stating something like this: "Our findings are inconclusive, and we are unable to determine whether your employer has violated the law. Therefore, we are closing our file, and here is your right-to-sue letter."
The good news is that if there is a strong evidence to support your claim, you don't have to wait for the DFEH to issue its findings, which can sometimes take many months or even more than a year. You can either contact the agency and asked that they close the investigation and issue you a right to sue letter, or you can have your attorney get a right to sue letter through DFEH online system in just a few minutes.