Cummins-Onan QG i error code 12 (QG i DF)
Over Voltage. Indicates the control is unable to maintain rated voltage. Service manual logic: output voltage over 130V - the inverter cuts AC output but the engine keeps running; the only listed repair is to replace the inverter. QG i DF dual-fuel family (QG 7000i DF = HGLCA, QG 4000i DF = HGLDA, QG 2800i DF = HGLEA) code table - distinct from the QG 2800i/2500i (HGLAA) table and from the HGJAA (0983-0501) and KY tables. The status indicator flashes a 1-digit code, or two sets of flashes (tens, pause, units) for a 2-digit code; flashing stops after 5 minutes and pressing STOP/PRIME 3 times within 5 seconds resumes it. The last fault logged keeps flashing after the condition is corrected.
What to check, and in what order, is in the app. A step-by-step flow walks this code with the pass/fail measurements, wiring schematics and procedures that go with it, and it works offline in the bay.
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- Operator Manual RV Generator Set HGLCA Spec A (QG 7000i DF), A079E225 Issue 1Cummins Onan
- Operator Manual RV Generator Set HGLDA Spec A (QG 4000i DF), A080H582 Issue 1Cummins Onan
- Operator Manual RV Generator Set HGLEA Spec A (QG 2800i DF), A080H579 Issue 1Cummins Onan
- Service Manual RV Generator Set HGLCA Spec A (QG 7000i DF), A079E227 Issue 1Cummins Onan
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