What Motor Under Voltage Error Means
Three flashes then five means the motor control has reported a low voltage condition at its own supply. Viking's FDB451 dishwasher service manual (2012, page 12) puts house voltage at the head of the list, then the terminal block, then the AC connection to the machine control, then the link between machine control and motor control.
Common Causes of Motor Under Voltage Error
- Supply voltage at the house below specification
- Loose connection at the dishwasher's terminal block
- AC connection to the machine control degraded
- Link between the machine control and the motor control failing
🔧 One Safe Check You Can Try
This is one of the few dishwasher codes that points outside the appliance first. Note whether lights dim elsewhere in the house when a large load starts, and whether the problem is worse at particular times of day - both are useful to whoever attends.
⚠ Why You Shouldn't Go Further Than That
- Viking's first check is house voltage, and measuring that under load is electrician's work rather than an appliance check.
- A loose terminal block connection heats where it is loose, and heat at a terminal is a condition to have looked at rather than one to keep loading.
- Fitting a motor control against a supply problem puts a new board onto the same under-voltage that upset the last one.
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.