What 3421 Means
The control ran the motorised door lock and the latch did not reach either end of its travel in the time allowed. Wolf's M Series Troubleshooting Manual gives 3421 for the upper cavity and 3422 for the lower, both at priority 2. This is the mechanism failing to complete its journey, as opposed to the board failing to drive it.
Common Causes of 3421
- A latch binding on debris or on a strike plate that has shifted
- A lock motor that has weakened and cannot complete its travel under load
- Spillage or cleaning residue that has stiffened the mechanism
🔧 One Safe Check You Can Try
Let the cavity cool completely, then look at whether the latch bar is stopped part-way. Listen too - a motor you can hear working against a jam tells a different story from silence.
⚠ Why You Shouldn't Go Further Than That
- Wait for the cavity to cool before touching the door: lock timeouts cluster around self-clean, when the oven is at its hottest.
- Levering a half-travelled latch damages the strike and turns an electrical problem into a door and frame repair.
- The lock motor is driven from the relay board on line-adjacent wiring, so testing it means isolating the appliance.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.