Dacor Range Oven Cooktop Error Code C77

The C77 error code on Dacor Heritage series ranges and ovens indicates that the main control board has lost communication with the keypad or has failed to detect the keypad entirely. This is a keypad detection fault, meaning the control board is either not receiving any signal from the keypad interface or is receiving a signal that falls outside acceptable parameters. The keypad is the primary user input device, and when the control board cannot establish or maintain a connection with it, the appliance will display C77 and suspend normal operation to prevent unsafe or unpredictable behavior.

The communication between the keypad and the control board typically runs through a ribbon cable or wiring harness connector. Failures in this connection are among the most common root causes of C77. Loose, corroded, or physically damaged connectors can interrupt the signal path entirely. In some cases, a faulty keypad assembly itself is responsible, as internal component failure within the keypad can prevent it from responding to polling signals sent by the control board. Less frequently, the control board itself may be the source of the fault if its keypad detection circuit has failed.

Diagnosing C77 requires a systematic check of the physical wiring harness from the keypad to the control board, inspection of all connector pins for damage or corrosion, and evaluation of the keypad assembly for any signs of moisture intrusion or physical damage. If the wiring and connectors appear intact and properly seated, the keypad assembly should be tested or replaced. If a replacement keypad does not resolve the fault, the control board should be evaluated as a secondary suspect.