1 EXHIBIT 23(a) CONSENT OF ERNST AND YOUNG, LLP, INDEPENDENT AUDITORS We consent to the incorporation by reference in the registration statement on Form S-8 of Comerica Incorporated, pertaining to the registration of 500,000 shares of common stock with respect to the Comerica Incorporated Preferred Savings Plan, of our report dated January 22, 1997, with respect to the consolidated financial statements of Comerica Incorporated, incorporated by reference in the Annual Report (Form 10-K) for the year ended December 31, 1996 filed with the Securities and Exchange Commission. March 31, 1997 E-3