4C on a Samsung dishwasher indicates a water supply problem. The control board expects the tub to fill to a certain level within a set time, and when incoming water doesn’t arrive fast enough — or at all — it halts the cycle and shows the code.
Likely Causes
- The water supply valve under the sink not fully open
- A kinked or crushed supply line behind or beneath the dishwasher
- A clogged inlet water valve screen where the line connects to the machine
- Low household water pressure at the kitchen connection
What to Check
Open the cabinet under the sink and confirm the shutoff valve feeding the dishwasher is turned fully on — these are sometimes bumped closed during other plumbing work. Check that the flexible supply line running to the machine isn’t pinched behind the unit, which is common after an install or move. If you’re comfortable pulling the dishwasher slightly forward, the inlet valve’s small mesh filter can collect sediment over time and may need a gentle rinse.
Run a normal cycle after confirming water flow. If the tub fills and the cycle proceeds, the supply line was the issue. If 4C returns with confirmed water pressure at the valve, the inlet valve solenoid inside the dishwasher is the more likely failure point.
When to Call a Technician
An inlet valve that doesn’t open reliably needs testing with the right equipment rather than trial and error. Our Samsung dishwasher repair technicians can confirm the failed component quickly. See our dishwasher repair or replace guide for help deciding on an older unit.
This is an independent repair service and is not affiliated with Samsung.
