What causes the 1906 code on a Generac generator?

Tripped main line circuit breaker on the generator: First thing to check — breaker on the side/back of the unit popped open. Loose AC sense wiring at controller: Connector backed out of the controller. Failed AVR: No output to sense.

Generac · Generator Moderate

1906 — Loss of AC Sense

Controller can no longer sense generator AC output even though engine is running. Often a wiring issue between the alternator and controller, or a failed sense circuit.

Keep using it?: Yes, with caution
DIY difficulty: Moderate
Verified against: generac.com ↗

How to fix it

Press the main line breaker on the generator firmly to OFF then back to ON.
Power down, pull controller fuse, and reseat the AC sense connector at the controller.
Measure AC output at the alternator with a multimeter while running in Manual — should be 240V at no-load.
If 0V output, AVR or stator has failed — call dealer.

Why it happens

Typical signs: 1906 fault · Engine running but unit does not transfer · No AC voltage at the panel

Tripped main line circuit breaker on the generator First thing to check — breaker on the side/back of the unit popped open.
Loose AC sense wiring at controller Connector backed out of the controller.
Failed AVR No output to sense.
Failed stator Open or shorted stator winding.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Main line circuit breaker Common replacement
Amazon →

More Generac generator codes

1100 1100 — Overcrank (Engine Failed to Start) 1300 1300 — Low Oil Pressure Shutdown 1501 1501 — RPM Sense Loss 1505 1505 — Overcrank (Variant — Try Again) 1600 1600 — Underspeed 1800 1800 — Overvoltage

All Generac codes → All generator codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: generac.com.