Fault 36

Onan Generator: “Fault 36”

warning RV generator fault codes

Safety This is a fuel-burning (gasoline or LPG) engine. If you smell gasoline or propane, stop, do not crank or create sparks, and ventilate before troubleshooting. Let hot engine parts cool before touching them. Never run a generator in an enclosed space - exhaust contains deadly carbon monoxide.

What it means

Engine Stopped fault. The engine stopped on its own without the controller commanding a shutdown. Despite being one of the most-searched Onan codes, code 36 is NOT overspeed (that is code 31) - it most often means the genset simply ran out of fuel, lost spark, or stalled from a fuel/air problem. Read as three blinks, a pause, then six blinks.

Most likely causes

  1. Out of fuel - on shared tanks the generator pickup tube sits higher than the vehicle engine pickup, so the genset runs dry first (often around 1/4 tank) most likely
  2. LPG supply too low or, on cold days, insufficient vaporization rate to meet demand common
  3. Weak or fouled spark - loose spark-plug leads or worn spark plugs common
  4. Clogged air cleaner restricting airflow less common
  5. Mechanical damage or other engine fault rare

Safe checks you can do yourself

How to reset / clear Fault 36

  1. Correct the underlying cause (usually refuel) first.
  2. On gasoline models, prime the fuel system by holding the control switch at Stop/Prime for about 30 seconds, then attempt a restart.
  3. Wait about 5 seconds for the controller to reset between start attempts.
  4. Note: the controller logs the last fault and will keep blinking it for ~5 minutes (15 minutes on HGJAA series); pressing Stop three times within 5 seconds restores the blink display. The logged code clears on the next successful run/start cycle.

When to call a technician

Fuel and spark are confirmed good but the genset still stops on code 36, or you suspect mechanical damage. Internal repairs should go to an authorized Onan/Cummins dealer.

Accuracy notes

The same number is filed differently by series. On the air-cooled KY and KYD sets it is 'Engine Stopped Fault — engine stopped without command by controller', with no numeric definition. On the Quiet Diesel it is 'Mechanical Fault', defined as engine speed falling below 1000 rpm for half a second without the controller asking for it. It is not overspeed; overspeed is code 31.

Applies to

Onan RV QG / KY series RV gensets (e.g. KY Spec J-N) · Onan Marquis / Microlite / Emerald style RV gensets using the blink-code controller · HGJAA / HGJAB-class units (note longer 15-minute blink retention on HGJAA)

FAQ

What does Onan Generator code "Fault 36" mean?

Engine Stopped fault. The engine stopped on its own without the controller commanding a shutdown. Despite being one of the most-searched Onan codes, code 36 is NOT overspeed (that is code 31) - it most often means the genset simply ran out of fuel, lost spark, or stalled from a fuel/air problem. Read as three blinks, a pause, then six blinks.

How do I reset Onan Generator Fault 36?

Correct the underlying cause (usually refuel) first. On gasoline models, prime the fuel system by holding the control switch at Stop/Prime for about 30 seconds, then attempt a restart. Wait about 5 seconds for the controller to reset between start attempts. Note: the controller logs the last fault and will keep blinking it for ~5 minutes (15 minutes on HGJAA series); pressing Stop three times within 5 seconds restores the blink display. The logged code clears on the next successful run/start cycle.

What is the most common cause of Fault 36 on a Onan Generator?

The most likely cause is out of fuel - on shared tanks the generator pickup tube sits higher than the vehicle engine pickup, so the genset runs dry first (often around 1/4 tank).

Related · Onan generator

Fault 4
Overcrank — a first-level fault shown as four blinks. The starter turned… Fault 31
Overspeed fault. The engine speed exceeded 3400 rpm, so the controller… Fault 3
Service check — a first-level fault shown as three blinks. Three blinks… Fault 32
Low cranking speed fault. During start the engine cranked slower than…

Sources

● Checked against 3 manufacturer documents · Last verified 2026-08-07 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual. How we verify