As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE DIGITAL FLIGHT GUIDANCE COMPUTER DFGC FAILED DUE TO THE MACH SPEED INDICATOR DOES NOT APPEAR AND ALTITUDE HOLD INDICATOR WAS AFFECTED. THE DFGC WAS DEFERRED BY MEL 22-15. DURING OVERNIGHT SERVICE THE DFGC WAS REPLACED IAW MM 22-01-01 AND WIRING WAS VERIFIED IAW WDM 22-16-11, TEST CORRECT.