Fault codes / Progressive EMS / E-4
Progressive EMS code E-4
What it means: Line 1 low voltage, below 104V.
What to check
Meter the pedestal with no load, then with the AC running. Big sag under load is pedestal or cord voltage drop: hot plug blades, a long or undersized extension, or a park at capacity on a hot afternoon. Shed load.
Tech detail
Feel the cord ends. A warm plug is resistance.
Learn the system
- Shore power: 30A vs 50A
- Breakers, GFCIs and the EMS
- The lost neutral (50A danger)
- Transfer switches and generator power
Practice it on a service call
Guided diagnosis
Other Progressive EMS codes
- Progressive EMS code E-0 Normal, power passing
- Progressive EMS code E-1 Reverse polarity: hot and neutral swapped
- Progressive EMS code E-2 Open ground
- Progressive EMS code E-3 Line 1 high voltage, above 132V
- Progressive EMS code E-5 Line 2 high voltage, above 132V (50A only)
- Progressive EMS code E-6 Line 2 low voltage, below 104V (50A only)
- Progressive EMS code E-7 Frequency high, above 69 Hz
- Progressive EMS code E-8 Frequency low, below 51 Hz
- Progressive EMS code E-10 Surge module used up
- Progressive EMS: Display dark, no power Open neutral (no code for it)
- Surge Guard: Open ground No ground at the pedestal or in the cord
- Surge Guard: Reverse polarity L1 or L2 landed on neutral or ground
- Surge Guard: L1 high / L2 high Above 136V on that leg
- Surge Guard: L1 low / L2 low Below 102V on that leg
- Surge Guard: L1 amps / neutrip Current over 110% on a leg, or neutral over 130% (50A)
- Surge Guard: Recept overheat Plug or receptacle running hot
- Surge Guard: GND high Voltage on the ground conductor
- Surge Guard: Open neutral Neutral lost on the coach side
- Surge Guard: Replace surge Surge protection expended
Full field guide: Progressive Industries EMS and Surge Guard
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.