What C4 Means
C4 is a temperature sensor problem — the control board isn't getting a valid reading from the wash-water thermistor.
Common Causes of C4
- Sensor has failed
- Sensor wiring connection has failed
🔧 One Safe Check You Can Try
There's no safe homeowner check — the sensor is mounted inside the tub wall or sump area, not accessible without partial disassembly.
⚠ Why You Shouldn't Go Further Than That
- Confirming which of the two failed means testing sensor resistance directly with the unit open.
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.
Technical Reference
- Code
- C4
- Appliance
- Monogram dishwasher
- Maker documentation
- Monogram owner manuals and use & care guides
- Checked
- September 2026
Code meanings can change between control generations. Before acting on a code, match the full model number on your appliance's rating label against the manual for that model. We are an independent repair service, not affiliated with Haier US Appliance Solutions, Inc.