About Generator Fault Codes

What your standby or portable generator's fault code, blink pattern, or warning display actually means.

What this site is

Generator Fault Codes is a reference for standby and portable generator fault codes across manufacturers. When a generator locks out or a warning light comes on, the actual explanation usually lives inside a PDF service manual, an owner's manual most people never open, or scattered forum threads of varying reliability. The goal here is one clear page per code: what it means, what commonly causes it, what's safe to check yourself, and where the line is between a homeowner fix and a technician call.

Independence

This site is not affiliated with, endorsed by, or sponsored by Generac, Kohler, Briggs & Stratton, or any other generator manufacturer. Brand and model names appear here only to identify which equipment a given code applies to — that's nominative use, not a partnership. If a page ever reads like it's speaking for a manufacturer, that's a bug; please flag it.

How the pages are written

Pages are drafted with AI assistance from manufacturer service and owner's manuals, and from documented repair-cost references, with factual claims checked against a listed source before publishing. Fault code meanings are facts and are reproduced as facts, in our own words — manufacturer manual text is not copied. Codes and their meanings can vary between models and even between controller generations from the same manufacturer, so every code page states which equipment and controller it applies to. A code is only published here if its meaning could be verified against a real source; if it couldn't be, it's left out rather than guessed at.

Nothing on this site is a fabricated testimonial, review, or author persona, and no repair-cost figure is presented with false precision — costs are shown as ranges, sourced from named contractor-rate aggregators, because that's what the underlying data actually supports.

Coverage

28 codes documented so far, across 3 manufacturer groups — Generac, Kohler, and Briggs & Stratton
Each code page states the exact controller or product line it applies to (for example, Generac's Evolution/Nexus controllers, or Kohler's RDC2/DC2 controllers), since the same brand can use more than one diagnostic system across its lineup
Coverage is expanding brand by brand; a code that can't be verified against a real manufacturer source is left off the site rather than published with a guess

Safety framing

Standby generators run on liquid propane or natural gas and produce mains-voltage output; portable generators produce mains-voltage output and burn gasoline. Both can kill through carbon monoxide poisoning, electrocution, or fire if handled wrong. Every code page separates what's reasonable for a homeowner to check — oil level, battery terminals, a visible fuel valve, an obviously blocked vent — from what belongs to a licensed electrician or generator technician: fuel-system work, transfer-switch wiring, alternator or voltage-regulator diagnosis, and anything involving the generator's live output. When a page says to call a professional, that's the actual safety line, not a hedge.

Corrections

If a page is wrong, the fastest way to establish that is the source: every planned code page lists the manual or reference it was built from, so the claim can be checked against the same document rather than taken on trust. Where a manufacturer's own documentation is ambiguous or contradictory, that gets stated on the page rather than resolved by guessing.

This site is a reference, not a substitute for a licensed electrician or generator technician. Generators involve mains-voltage output and, on standby units, a live fuel-gas supply. Anything involving wiring, the transfer switch, or the fuel system should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.