Dometic P4 fault code — Rooftop air conditioner
Applies to: FreshJet Series 4, FreshJet Series 7, FJX4333EEH, FJX7333IHP
What P4 means
The Dometic FreshJet FJX operating manual lists P4 as discharge tube overheat protection.
Owner-safe checks
- Record P4, selected mode, setpoint, outdoor conditions, and how long the unit had been running.
- Stop FreshJet operation from normal controls if the code returns.
- Keep visible air intake openings, air nozzles, and ventilation grilles clear before service.
Service-only work
- Discharge tube temperature protection, sealed-system condition, refrigerant-circuit work, fans, sensors, and rooftop compartment diagnosis should be handled by authorized Dometic service or qualified RV HVAC personnel.
Safety boundary
Disconnect power before any FreshJet service. Refrigerant-circuit, sealed-system, sensor, fan, drive, electrical protection, roof seal, and internal component work is for authorized Dometic service or qualified RV HVAC personnel.