What E4 Means
E4 is the partner to E3 on the RF24D refrigerated drawers: the DCS service manual names it the display thermistor, “sensor A”, reading out of range. This is the sensor whose temperature you see on the panel and that the control uses to decide when to run the compressor, so with E4 showing the drawers can drift warm or run constantly.
Common Causes of E4
- Display thermistor wire disconnected at its connector
- Shorted thermistor leads inside the cabinet wall channel
- Thermistor failed from moisture in an outdoor installation
🔧 One Safe Check You Can Try
Put a thermometer in the top drawer and check it after an hour with the drawers closed. If the reading is above 40°F, move perishables. Try one power reset at the outlet. If E4 returns, keep the drawers closed and book service; food safety depends on a working sensor.
⚠ Why You Shouldn't Go Further Than That
- The sensor lead runs from the drawer cavity to the control through the cabinet, and pulling it without releasing its clips breaks the wire inside the foam.
- An out-of-range reading can come from the connector at the board as easily as from the sensor, and only a resistance check tells them apart.
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.