Onan QG / Marquis Gold / HGJA (KY) series fault codes
The 8 fault codes below are the ones that apply to this Onan generator family. The other 10 Onan generator codes in our database belong to different model families — they are listed further down so you do not troubleshoot against the wrong table.
Covered model numbers
HGJAAHGJABHGJACHGJADHGJAEHGJAFKY seriesMarquis GoldQG 4000QG 5500
Not on the list? Check the rating label before you troubleshoot — the code table below will not apply. Where to find it →
Fault codes on the Onan QG / Marquis Gold / HGJA (KY) series
Service check — a first-level fault shown as three blinks. Three blinks is not the fault i… Fault 13 warning
Undervoltage fault. The controller could not hold the generator's AC output at rated volta… Fault 15 warning
Underfrequency fault. The engine governor could not keep the engine spinning fast enough t… Fault 19 warning
Governor actuator fault. The controller detected an open or shorted circuit in the electro… Fault 27 warning
Voltage sense fault. The controller was unable to sense the generator's output voltage, so… Fault 29 warning
High battery voltage fault. The voltage across the genset's starting battery system was ab… Fault 32 warning
Low cranking speed fault. During start the engine cranked slower than about 180 rpm for mo… Fault 38 warning
Overcurrent (field overload) fault. The generator saw excessive current from low-power-fac…
Codes that do not apply to this model
These 10 codes exist on other Onan generators. If your unit is showing one of them, it is not from this family — re-check the model number on the label before acting on any of these.
Engine over temperature — a first-level fault shown as one blink. On a liquid-cooled Quiet… Fault 2 (Low Oil)
Low oil pressure — a first-level fault shown as two blinks. The Quiet Diesel manual define… Fault 4
Overcrank — a first-level fault shown as four blinks. The starter turned the engine and it… Fault 12
Overvoltage fault. The controller could not keep the output voltage at the rated value (ou… Fault 14
Overfrequency fault. The engine governor could not hold the rated output frequency and the… Fault 22
Governor actuator overload. The controller had to hold the governor actuator at full duty … Fault 24
Faulty engine temperature sender. After ten minutes of normal running the controller check… Fault 31
Overspeed fault. The engine speed exceeded 3400 rpm, so the controller shut the generator … Fault 36
Engine Stopped fault. The engine stopped on its own without the controller commanding a sh… Fault 57
Overprime. A control switch — the one on the genset or the remote one inside the vehicle —…
Where the model number is
On the genset housing near the control panel; the serial plate carries both the model/spec number and the controller family, which is what decides the code table.
Sources
- Onan Troubleshooting Codes (Service Manual Table 5) — Cummins Onan (hosted by Heartland Owners) (Overcurrent (Field Overload) Fault — Code No. 38)
- RV Generator Handbook (Cummins Onan) — Cummins Power Generation (Fault Codes — blink-code readout procedure)
- Operator Manual — RV Generator Set KY (Spec J–N) — Cummins Inc. (Onan) (981-0159 (Issue 9), Section 4 Troubleshooting, Table 2)
- Cummins Onan RV Generator Handbook (2019 edition) — Cummins Inc. (hosted by Forest River) (Fault Codes, p. 38)
- Operator Manual — RV Generator Set HDKCA / HDKCB (Spec A–E) — Cummins Inc. (Onan Quiet Diesel) (0981-0173 (Issue 10), Section 4 Troubleshooting, Table 4-1)
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