There isn't a set deadline, but I would have to wonder why you would be making such a disqualification motion so close to trial.
Under Code of Civil Procedure section 128(5), the Court has the power to control in furtherance of justice, the conduct of its ministerial officers. This permits the Court to issue an order that disqualifies an attorney from representing a party. (Henriksen v. Great Am. Sav. & Loan (1992) 11 Cal. App. 4th 109, 113.)
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, consult with your own attorney.
While I cannot give you legal advice in this forum, I am unaware of any specific deadline. However, you should move promptly after discovering the grounds for disqualification. If you unreasonably delay, the court may view it as a litigation tactic and could choose to deny the motion.
THIS RESPONSE IS INTENDED TO CONVEY GENERAL INFORMATION ONLY. IT SHOULD NOT BE RELIED UPON OR TAKEN AS LEGAL ADVICE. FURTHER, THIS RESPONSE IS NOT INTENDED TO AND DOES NOT CREATE AN ATTORNEY-CLIENT RELATIONSHIP.
I agree with Mr. Chen's answer. The court would probably look at a number of factors including the reasonableness of your motion, timing of you discovering facts causing you to bring such a motion, prejudice involved, and whether your request is legitimate.