Cal. Probate Code § 2650

A guardian or conservator may be removed for any of the following causes: (a) Failure to use ordinary care and diligence in the management of the estate. (b) Failure to file an inventory or an account within the time allowed by law or by court order. (c) Continued failure to perform duties or incapacity to perform duties suitably. (d) Conviction of a felony, whether before or after appointment as guardian or conservator. (e) Gross immorality. (f) Having such an interest adverse to the faithful performance of duties that there is an unreasonable risk that the guardian or conservator will fail faithfully to perform duties. (g) In the case of a guardian of the person or a conservator of the person, acting in violation of any provision of Section 2356. (h) In the case of a guardian of the estate or a conservator of the estate, insolvency or bankruptcy of the guardian or conservator. (i) In the case of a conservator appointed by a court in another jurisdiction, removal because that person would not have been appointed in this state despite being eligible to serve under the law of this state. (j) In any other case in which the court in its discretion determines that removal is in the best interests of the ward or conservatee; but, in considering the best interests of the ward, if the guardian was nominated under Section 1500 or 1501, the court shall take that fact into consideration.