Troubleshooting guide
RV thermostat communication error
Use this when an HVAC thermostat shows Er, E1, E3, or zone/control-box communication terms.
Use this atlas to identify likely meaning and prepare for service. Shut off power, LP gas, fuel, or water when a listed appliance condition involves flame, gas smell, exhaust, generator shutdown, high temperature, moving jacks/slides, refrigerant, 120 VAC, control boards, repeated ignition failure, or a persistent lockout. Call the appliance maker, RV dealer, or a qualified RV technician for repair.
Owner-safe checklist
- Record thermostat model and affected zone.
- Turn HVAC off if the zone is not responding.
- Do not open rooftop electrical compartments.
Code tables for these appliances
- Coleman-Mach RV thermostats 14 codes
- Dometic RM10 / RMS10.5 refrigerators 52 codes
- Dometic RMD10, RMD10.5 and RML10.4 refrigerators 17 codes
- Dometic RM3762 / RM3962 refrigerators 6 codes
- Dometic RV thermostats (CCC2, Single Zone LCD, Bluetooth CT) 8 codes
- Furrion rooftop air conditioners and thermostats 13 codes
Related fault codes
- Dometic refrigerator code E0: No communication between the display and power module
- Dometic refrigerator code E03
- Dometic thermostat code E1
- Dometic thermostat code E7: Loss of normal AC power to all system power module boards; the system shuts down
- Dometic thermostat code E8: Invalid zone configuration with heat pump and heat strip DIP switches both on in one zone; affected-zone operation locks out
- Dometic thermostat code E9
- Furrion rooftop air conditioner code E1: Indoor temperature sensor out of order; system will shut down
- Furrion rooftop air conditioner code E2: Evaporator temperature sensor out of order; system will shut down
- Furrion rooftop air conditioner code E3: Loss of communication between the thermostat and control box; system will shut down
- Furrion rooftop air conditioner code E4: Condenser temperature sensor out of order; system will shut down
- Furrion rooftop air conditioner code E5: Outdoor temperature sensor out of order; system will shut down
- Furrion thermostat code E3
- Furrion thermostat code E6: Thermostat indoor temperature sensor out of order; system will shut down
- Furrion thermostat code lo: Insufficient low level of +12 V power supply; system will shut down
- Furrion thermostat code E1: Control box indoor temperature sensor out of order; system will shut down
- Furrion thermostat code E2: Evaporator temperature sensor out of order; system will shut down
- Furrion thermostat code E4: Outdoor coil sensor out of order; system will shut down
- Furrion thermostat code E5: Outdoor ambient air temperature sensor out of order; system will shut down
- Dometic refrigerator code E13: Internal communication error; gas operation is not possible
- Dometic refrigerator: display module limp mode
Official sources
Coleman-MachColeman-Mach 9330-33 Multiple Zone Thermostat Controller SystemFurrionFurrion Heat Pump Single Zone Wall Thermostat Quick Start GuideDometicDometic RM3762 RM3962 Refrigerator Operating InstructionsDometicDometic RMD10T, RMD10XT Absorption Refrigerator Operating ManualDometicDometic Single Zone LCD Thermostat Operating InstructionsDometicDometic RM10.5/RMS10.5 Absorption Refrigerator Operating ManualDometicDometic RMD10.5 Absorption Refrigerator Operating ManualDometicDometic RML10.4 Absorption Refrigerator Operating ManualDometicDometic 3316420.XXX Bluetooth CT Thermostat Operating InstructionsFurrionLippert QR-187 Correcting E3 Error Code Of Furrion Enhanced Multi Zone Wall ThermostatFurrionLippert QR-155 Furrion Thermostat and Controller Compatibility Overview