REFERENCE 45-00 · DIAGNOSTICS & FAULT CODES
OEM Fault Code Index: Onan & Dometic
The first two brand indexes in an ongoing fault-code reference — more brands (Norcold, Lippert, Suburban/Atwood, Progressive Dynamics, Xantrex) coming as we build this out.
Onan RV Generator Blink Codes
On a shutdown, the status light blinks a repeating code. To retrieve it manually: press the generator control button 3 times within 5 seconds, then count the blink pattern.
| Code | Meaning |
|---|---|
| 1 | High engine temperature |
| 2 | Low oil pressure |
| 4 | Overcrank — no start after cranking time expired |
| 12 | Overvoltage |
| 13 | Undervoltage (generator output) |
| 14 | Over frequency |
| 15 | Under frequency |
| 19 | Governor actuator overload |
| 27 | Voltage sense error |
| 29 | High battery (starting) voltage |
| 36 | Engine stopped unexpectedly (no shutdown fault signal received) |
| 38 | Overcurrent / field overload |
| 41 | Generator rotor fault |
| 42 / 43 | Controller processor fault |
| 45 | Speed sense fault |
| 47 | Ignition fault |
| 48 | Generator field sense fault |
Codes vary somewhat by Onan/Cummins model and controller generation — confirm against the operator manual for your specific genset (e.g. Cummins RV Generator Set, Spec J–N) before acting on a code, especially for engine-safety shutdowns (codes 1, 2, 4).
Dometic Refrigerator Error Codes
Important: Dometic fridge error codes are not standardized across product lines — an E03 on an RM-series two-digit-code fridge means something different than an E03 on an RMD 10-series or a portable CFX unit. Confirm your exact model before diagnosing off any code table, including this one.
| Code | General Meaning | Owner Action |
|---|---|---|
| E0 | Power loss / no communication between display and power module | Check 12V and AC power supply to the fridge first — often a fuse or connection issue, not the fridge itself |
| E03 (RUC series, confirmed via Dometic support) | Fault requiring authorized service | Dometic’s own documentation states this code can only be resolved by an authorized service provider — root cause is not published for DIY diagnosis |
| W05 / W06 / E07 / E08 (RMD 10-series) | Warning/error family specific to the 10-series platform | Reset per your model’s manual (commonly: hold the encoder/reset button ~3 seconds); if it returns, service is needed |
Dometic does not publish detailed root-cause explanations for most of these codes to the general public — many genuinely require an authorized technician with model-specific service documentation and, for absorption units, cooling-unit-specific test equipment. Where we don’t have a verified answer, we’re not going to guess at one.
Related Reference Pages
Onan, Cummins & Honda Generator Guide
Dometic AC, Fridge & Awning Guide
Full Field Guide
⚠ Safety note: This page is for informational purposes only and is not a substitute for the advice of a qualified professional. Generator and refrigerator faults can involve fuel, high voltage, and (for absorption fridges) ammonia and hydrogen under pressure. Codes and meanings vary by model/year/platform — always confirm against your unit’s current OEM manual before acting. United Mobile RV LLC is not responsible for outcomes of DIY work performed using this reference. Rev. 1 — August 2026.
Throwing a code we didn’t cover, or one that keeps coming back? We diagnose it properly, on-site.