Dometic Air Conditioner: “E2”
warning RV air conditioner error codes
What it means
The indoor (return-air) temperature sensor is reading open-circuit or out of range. The system locks out all heating and cooling, but manual fan operation can still run.
Most likely causes
- Disconnected, broken, or out-of-range indoor temperature sensor most likely
- Loose or corroded sensor wiring/connector at the control board common
- Failed control board sensor input less common
Safe checks you can do yourself
- Power-cycle the system at the breaker to confirm the fault is persistent and not a one-time glitch.
- If the sensor connector is easily accessible at the thermostat or control box, check that it is fully seated and free of corrosion (do not cut or splice wiring yourself).
- Note whether fan-only mode still works, which is consistent with an indoor-sensor fault rather than a full communication failure.
How to reset / clear E2
- Turn the thermostat OFF.
- Remove power at the AC breaker for a minute, then restore power to clear a transient fault.
- If E2 returns immediately, the indoor sensor or its wiring needs inspection/replacement.
When to call a technician
If E2 persists after a power cycle, have a technician test or replace the indoor temperature sensor and check the control board input.
Applies to
Dometic Comfort Control Center 2 (CCC2) thermostat systems · Dometic Single Zone LCD thermostat systems
FAQ
What does Dometic Air Conditioner code "E2" mean?
The indoor (return-air) temperature sensor is reading open-circuit or out of range. The system locks out all heating and cooling, but manual fan operation can still run.
How do I reset Dometic Air Conditioner E2?
Turn the thermostat OFF. Remove power at the AC breaker for a minute, then restore power to clear a transient fault. If E2 returns immediately, the indoor sensor or its wiring needs inspection/replacement.
What is the most common cause of E2 on a Dometic Air Conditioner?
The most likely cause is disconnected, broken, or out-of-range indoor temperature sensor.
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Sources
- Comfort Control Center 2 Thermostat User's Guide — Section N, LCD Error Code (Error Code: E2) (Dometic Corporation)
- Single Zone LCD Thermostat User's Guide — LCD Error Code (Error Code: E2) (Dometic (via Prime Time RV component manuals))
Note: E2 = open/out-of-range indoor temperature sensor on both CCC2 and Single Zone LCD thermostats. Do not confuse with E3 (shorted indoor sensor).
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.