Fault codes / Progressive EMS / Display dark, no power
Progressive EMS: Display dark, no power
What it means: Open neutral (no code for it).
What to check
On 30A the display stays dark and power is refused. On 50A an open neutral shows up as one leg high and the other low. Check the neutral pin on the plug and the pedestal lugs.
Tech detail
Open neutral on a 50A coach puts up to 240V on 120V loads. Nothing runs until it is found.
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-4 Line 1 low voltage, below 104V
- 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
- 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.