Dacor Wall Oven U40 Error Code

When a Dacor wall oven shows U40 (upper or single oven) or L40 (lower oven), the relay board has reported a wiggler failure. A comparator circuit that verifies command states between the logic board and the relay board has failed. The entry comes from the service manual for 27-inch and 30-inch single and double ovens with touch-glass control, series not stated.

What happens

The control waits 60 seconds and then declares a fatal error because the wiggler is not in the proper state. No functions are available, so the oven cannot be used for cooking or cleaning until it is serviced.

What the manual points to

The listed source is a bad relay board. The check is to look over the communication lines and make sure all contacts are touching and plugged in correctly; the listed solution is to replace the relay board. That work belongs to a technician, so switch the power off at the breaker and call for service.

Codes that look similar

• U41 / L41 – relay board A/D error
• U42 / L42 – relay board E2 checksum failure
• U43 / L43 – no zero-cross signal on the relay board

Dacor wall oven repair in Los Angeles

A U40 or L40 needs a technician. Call (310) 742-1907 for Dacor oven repair in Los Angeles and have the model number, the code and a note of what the oven did before it stopped.

Source: Wall Oven Service Manual, Appendix B Error Code Troubleshooting Guide