What is the scope of cross-examination of a defendant in a personal injury trial?

"Although a defendant cannot be compelled to be a witness against himself, if he takes the stand and denies the evidence presented against him, the permissible scope of cross-examination is '"very wide."' [Citation.]" (People v. Hawthorne (2009) 46 Cal.4th 67, 99-100, disapproved on another point in People v. McKinnon (2011) 52 Cal.4th 610, 637-643.) Moreover, when the defendant chooses to testify, "his character as a witness may be impeached in the same manner as any other witness. [Citations.]" (People v. Wagner (1975) 13 Cal.3d 612, 618.) As has been previously stated, "'[t]here are . . . exceptionally few caveats to the proposition that the right to introduce evidence necessarily implicates the responsibility to permit it to be fairly tested.'" (People v. Seminoff (2008) 159 Cal.App.4th 518, 527.)