Norcold N4000 Error Codes: Complete Troubleshooting Guide (N4104, N4141, N4150)

14th Oct 2026

Norcold N4000 Error Codes: Complete Troubleshooting Guide (N4104, N4141, N4150)

Norcold N4000 Error Codes: Complete Troubleshooting Guide (N4104, N4141, N4150)

Every N4000 error code, shown on both control panels, with what it means and a step-by-step flowchart to fix it.

8
4
2
1

LED panel. Press ‹, □ and › together until the temperature bars change. Ignore the smallest bar; the other four are worth 8, 4, 2 and 1. Add up the lit bars. Shown here: 2 + 1 = code 3.

LCD panel. The code number shows next to the wrench symbol. No 12V means no code at all; with 12V, the blue power light is on.

Fits these models

N4104N4141N4150

The Norcold N4000 series, built by Thetford. 3-way: 12V DC, 120V AC and propane.

Jump to a code

POWER & DISPLAY

Nothing lights up

display stays dark

Display won’t turn on

Black display. No 12V, or a short outside the fridge.

Open the flowchart →

PROPANE

Burner, flame and gas valve

LED panelLCD panel

Code 1: Flame sensed with gas off

Gas valve not closing, or the board.

Open the flowchart →
LED panelLCD panel

Code 2: Burner control module

Wrong feedback from the burner control. Power board.

Open the flowchart →
LED panelLCD panel

Code 3: Gas lockout

No flame in 30 seconds. Gas, spark, burner, pressure.

Open the flowchart →

12V DC

Battery, DC heater and the engine signal

LED panelLCD panel

Code 4: DC heater not working

Off when it should be on. Fuse, heater or board.

Open the flowchart →
LED panelLCD panel

Code 5: DC heater stuck on

On when it should be off. Relay on the board.

Open the flowchart →
LED panelLCD panel

Code 6: 12V out of range

Below 10 V or above 15 V. Supply, fuse or solar.

Open the flowchart →
LED panelLCD panel

Code 7: No engine signal (D+)

Manual DC mode with no engine-running signal.

Open the flowchart →

120V AC

Shore power and the AC heater

LED panelLCD panel

Code 8: AC heater failure

Heater current far too low. Heater, fuse or board.

Open the flowchart →
LED panelLCD panel

Code 9: AC heater stuck on

On when it should be off. Relay on the board.

Open the flowchart →
LED panelLCD panel

Code 10: AC out of range

Outside 108 to 132 volts. Usually the source.

Open the flowchart →

CONTROLS & COOLING

Energy selection, communication and the sensor

LED panelLCD panel

Code 11: No energy source in AUTO

No AC, DC or gas available to run on.

Open the flowchart →
LED panelLCD panel

Code 12: Boards not communicating

Low 12V, resettable fuse, plugs, cable or a board.

Open the flowchart →
LED panelLCD panel

Code 13: Thermistor failure

Sensor not read. Runs on its backup timer.

Open the flowchart →
no error code

Not cooling well, no code

Weak on 12V, AC or propane. Thermistor first.

Open the flowchart →

Quick reference: test values

12V DC 10 to 15 volts, steady
120V AC 108 to 132 volts
D+ engine signal 10 to 15 volts with the engine running
LP gas pressure 10.5 to 11.5 in. water column
Electrode gap About 4 mm (5/32 in.) above the burner
DC heater, N4104 0.98 to 1.08 Ω, about 12 A
DC heater, N4141 / N4150 0.67 to 0.74 Ω, about 17 A
Thermistor Clipped to the 5th fin from the right
Comm line (code 12) About 5 V DC, white (+) to green (−)
N4150 parts   N4141 parts   N4104 parts   Parts diagrams
Still stuck? ask a tech with your model, serial number and the code you’re seeing.
Based on Thetford’s N4000 troubleshooting guide, with North American voltage and gas pressure values. The panels above are illustrations of each code.
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