Cummins-Onan QD error code 12 (QD)
Over-voltage — automatic shutdown (after voltage regulation was enabled, output rose above 150 VAC [125% of rated] for 75 ms, or above 138 VAC [115%] for 3 s). (Code 12, second-level)
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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- Onan RV Quiet Diesel Operator Manual 0981-0173 (HDKCA/HDKCB)
- Onan RV QD HDKCA/HDKCB Operator Manual 0981-0173 (rv-tech-resources/93-onan-qd-diesel/Onan_RVQD_HDKCA_HDKCB_Operator_0981-0173.pdf)
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