Manufacturer fault library

Cummins Onan RV generator fault codes

Match the blink code or display number, understand why the generator stopped, and follow only the owner-safe checks supported by the applicable Cummins manual.

10 code guides1 system100% source linked
Frequently searched

Common Onan generator fault codes

Code 36Engine stopped without a commandOpen Code 36 guide →Code 12Output over voltageOpen Code 12 guide →Code 14Output over frequencyOpen Code 14 guide →Code 15Output under frequencyOpen Code 15 guide →
Most searched Onan fault

Code 36: engine stopped

Code 36 means the generator stopped without receiving a stop command. Start with fuel level, the manufacturer's prime procedure, and an external air-filter check. Stop if you find a fuel leak or mechanical damage.

Open the complete Code 36 guide →
Onan Code 36 diagnostic sequence: check fuel, prime for 30 seconds, and check the air filter
Before troubleshooting

How to read an Onan fault code

Record the complete two-digit code before cycling power. On many models, the status light flashes the first digit, pauses, and then flashes the second digit.

Confirm the generator model and specification letter. A code meaning can be shared across families while the correct procedure and service boundary differ by model.

Use the guides below for external observations and safe first checks. Fuel-system, electrical, or internal mechanical work belongs with qualified generator service.

Generators

10 guides
Code 36Engine stopped without a commandRV generator sets; confirm the exact model manualCode 14Output over frequencyHGLAA and compatible controllers; verify model applicabilityCode 15Output under frequencyHGLAA and compatible controllers; verify model applicabilityCode 27PMA sense lostHGLAA and compatible PMA-equipped generator setsCode 12Output over voltageHGLAA and compatible controllers; verify model applicabilityCode 13Output under voltageHGLAA and compatible controllers; verify model applicabilityCode 19Throttle actuator circuit faultHGLAA and compatible controllers; verify model applicabilityCode 25Alternator over voltageHGLAA PMA-equipped generator setsCode 26Alternator under voltageHGLAA PMA-equipped generator setsCode 29Battery over voltageHGLAA and compatible controllers; verify model applicability