Fault codes / Dometic CCC2 / E4

Dometic CCC2 code E4

What it means: Outdoor temperature sensor open or out of range (heat pump models).

What to check

Reseat, ohm, replace.

Learn the system

• Rooftop AC
• Capacitors
• Airflow and coils
• Thermostats and AC control boards

Practice it on a service call

• AC hums and trips
• AC runs but barely cools
• AC ices up and barely blows

Guided diagnosis

• Air Conditioner
• Thermostat

Other Dometic CCC2 codes

• Dometic CCC2 code E1 Lost communication between thermostat and the rooftop control box
• Dometic CCC2 code E2 Indoor temperature sensor open or out of range
• Dometic CCC2 code E3 Indoor temperature sensor shorted
• Dometic CCC2 code E5 Freeze sensor open or out of range
• Dometic CCC2 code E6 Humidity sensor open
• Dometic CCC2 code E7 Loss of 120V to the rooftop unit
• Dometic CCC2 code E8 Invalid zone configuration: DIP switches
• Dometic CCC2 code E9 Invalid zone configuration

Full field guide: Dometic CCC2 thermostat

Codes come from the maker manuals and public service sheets. Your model's own chart always wins, and LP and 120 volt work belongs to a qualified technician.