Kohler generator code Voltage High
High severity — Output voltage exceeded about 120% of the system's nominal voltage for more than 2 seconds, triggering a protective shutdown to keep connected equipment safe.
Applies to: Kohler residential standby generators with an RDC2 or DC2 controller
What it means
Whatever's plugged into the generator when this fault trips just got saved a scare, not handed one: output climbing above roughly 120% of the system's rated voltage for more than two seconds is genuinely dangerous to connected equipment, and Kohler's controllers shut the unit down that fast specifically to protect it. Two seconds is a short window by design — sustained overvoltage can damage refrigerators, electronics, and anything else drawing power from the generator at the time, so the RDC2 or DC2 controller doesn't wait around to see if the reading was a fluke. Unlike a fuel or ignition fault, this one lives entirely in the generator's electrical output path, which changes what's actually safe for a homeowner to check.
Most common causes
Overvoltage almost always comes down to the voltage regulation system itself:
- Failed or miscalibrated voltage regulator
- Loose voltage-sensing wiring
- Stator or rotor winding fault
What you can check yourself
There's not much a homeowner can safely check here, but this much is fair game:
- Clear the fault and see whether it recurs immediately
- Visually check for loose sensing wires at the regulator with the unit fully powered down
Don't keep resetting and running the unit hoping it was a one-time glitch — a genuine voltage regulator fault will just repeat, and each cycle risks damaging whatever's connected the next time it trips.
All codes for this brand
Every Kohler generator fault code — full list with what differs between models.
Related codes: Voltage Low and EngineSpeed High. See the Generator Runs Then Shuts Down symptom page for related shutdown faults.