Generac Code 1300: Low Oil Pressure and How to Clear It
Code 1300 means the engine shut itself down to protect the crankshaft. The low oil pressure switch opened while the generator was running, the controller killed the engine, and it won't restart until you clear the alarm. Generac's fix is the one you'd guess: let it cool 30 minutes, check the dipstick, add oil if it's low, make sure the fill cap, drain cap, and filter are tight, look for leaks — then clear the alarm at the panel. If the oil level is correct and 1300 comes back, that's a dealer call: the switch, the wiring, or the engine itself.
| Code | 1300 (LOW OIL PRESSURE) |
|---|---|
| Applies to | Air-cooled home standby (Guardian, PowerPact, Next Generation) — Evolution / Evolution 2.0 / Sync and Power Zone 200 controllers |
| Severity | Unit will not run |
| DIY | DIY-friendly — owner can resolve it with the manual |
| Last checked |
What code 1300 means
Generac's code list is terse — "1300: Low Oil Pressure" — and its support article says the code "indicates the low oil pressure sensor has triggered a shutdown due to inadequate oil levels," with the usual reason being oil consumption, a leak, or skipped maintenance.
The alarm comes from a switch on the engine, and the name of that switch is the whole point: it reports pressure, not level. A low level is the ordinary reason pressure drops — the pump picks up air on a tilted pad or a cold crank — which is why Generac sends you to the dipstick first. But a correct level with a failed switch, damaged wiring to it, or a worn oil pump produces the same shutdown, and that is why the owner's manual ends its entry where it does.
Generac does not publish the pressure or the delay the controller uses on current air-cooled units, and no figure is given here for that reason. If a dealer quotes one for your generator, it came from their documentation rather than from anything Generac publishes to owners.
| Code | Display | Meaning (Generac wording) | Severity | DIY? |
|---|---|---|---|---|
| 1300 | LOW OIL PRESSURE | "The low oil pressure sensor has triggered a shutdown due to inadequate oil levels." Owner's manual: check the oil level and add oil as needed; if the level is correct, contact an IASD | Unit will not run | DIY-friendly |
How to clear Generac code 1300
A 1300 clears from the panel, but only clear it once the engine has cooled for at least 30 minutes and the oil reaches the FULL mark, with the fill cap, drain cap and filter hand-tight. If the oil level is correct and the alarm comes back, both owner's manuals send you to a dealer. The key presses for each controller are on Generac lights and alarms.
Generac's 1300 article (Sep 17, 2026), in its order:
- "Allow the generator to cool." It asks for "at least 30 minutes to avoid potential injury or inaccurate readings."
- "Check and refill oil." "Confirm that oil dipstick is fully inserted, and that the oil fill cap, oil drain cap, and oil filter are hand-tightened."
- "Check for oil leaks." "Inspect the generator for any visible oil leaks and address them as necessary."
- "Clear the alarm and reset." Its warning with that step: "Never start the generator while under load."
The owner's manuals' LOW OIL PRESSURE entry is the same on both lines — "Check oil level and add oil as needed. If oil level is correct, contact an IASD." (Guardian A0001846499 Rev. C, p. 34; Next Generation A0004332577 Rev. C, p. 37). In a long outage the article adds a rule that applies whether or not 1300 ever appeared: "the unit is required to be shutdown every 24 hours, for 30 minutes to allow the unit to cool and the oil levels to be checked."
Checking the oil after a 1300 shutdown
- Read the dipstick cold. Low → add the correct oil (table below) to the full mark, no higher. Overfilling foams the oil and can trip the same alarm.
- Was it low? → go to step 2 anyway. Oil doesn't leave on its own.
- Full and clean? → step 4.
- Where did the oil go? Air-cooled Generacs run hard and hot, and some consumption between services is expected — which is exactly why Generac asks for the level to be checked every 24 hours of continuous running. A level that has fallen far enough to trip a shutdown still needs explaining. Check the drain hose and cap (many units route a drain hose to the front), the filter gasket, the valve cover gaskets and the crankcase breather. A wet spot under the unit, or oil on the enclosure floor, tells you where to look.
- Leak found at a cap or filter → tighten, top off, clear, retest.
- Leak at a gasket → dealer.
- When was the last oil change? Schedule A is every two years or 200 hours (first change at 25 hours). Old oil thins, and a plugged filter starves the switch. If it's overdue, do the service now (oil + filter 070185ES), then clear.
- Level is fine and it still trips? Then it is the switch, its wiring, or genuine low pressure. Heat, vibration and rodents all damage wiring inside an enclosure, so a look costs two minutes and is worth reporting. The measurement is not yours: it takes a mechanical gauge on a running engine, and the owner's manual says plainly that a correct oil level with this alarm goes to an IASD.
- Is it the grade your manual specifies? The 2023 Guardian manual and the Next Generation manual call for Generac's 5W-20 gaseous engine oil after the 25-hour break-in; the 2016, 2017 and 2020 manuals specify "Synthetic SAE 5W-30 for all temperature ranges." The full chart by kW is on the Generac oil capacity chart.
Oil type and capacity (from Generac's manuals)
| Unit | Engine | Oil capacity (with filter) | Oil grade (manual year) | Where verified |
|---|---|---|---|---|
| 10 kW | 460 cc | approx. 1.1 qt (1.03 L) | 5W-20 GEO after 25-hr break-in (2023); synthetic 5W-30 (2020) | Owner's manuals A0001846499 / A0000973303 |
| 14–18 kW | 816 cc twin | approx. 2.2 qt (2.1 L) | same | Owner's manuals A0001846499 p. 9 / A0000973303 p. 11 |
| 20–26 kW | 999 cc | approx. 1.9 qt (1.8 L) | same | Owner's manuals; 20–24 kW spec sheet |
| Next Generation 10 / 14–18 / 22–28 kW | 459 / 817 / 997 cc | approx. 1.4 qt (1.3 L) / 2.5 qt (2.4 L) / 2.2 qt (2.1 L) | 5W-20 GEO after 25-hr break-in | Owner's manual A0004332577 p. 14 |
| Oil filter | 070185ES (older 070185E) | air-cooled Guardian and Next Generation | Owner's manuals A0001846499 p. 9, A0004332577 p. 15, 0L6629 p. 9 |
Oil must meet API service class SJ, SL, or better. Generac sells its GEO oil and the filter in model-number-keyed maintenance kits; the kit article on its support site lists current numbers.
For the full model-by-model table — including portable Generac models, oil-change intervals, and current versus older manual guidance — see the Generac generator oil type and capacity guide.
A low-oil-pressure switch part number isn't shown here because none could be confirmed on a Generac or authorized-dealer page — the numbers on auction sites vary by engine and pressure rating, and the wrong one will either nuisance-trip or never trip.
When low oil pressure needs a Generac dealer
- Oil level and grade are correct and 1300 returns.
- You found oil at a gasket, the breather, or inside the enclosure rather than at a cap or filter.
- The engine ran for any length of time with the dipstick below the low mark — ask for a pressure test before the next outage.
- The unit knocks, smokes, or sounds different after the reset.
- Generac support: 1-888-436-3722. Warranty work goes through an Independent Authorized Service Dealer.
Shutdowns that can look like low oil pressure
A unit that starts, runs a few seconds, and shuts down with no oil alarm is more likely showing 1505 RPM Sense Loss. If 1300 shows up alongside a 1400 High Temperature, stop and call — the two together suggest the engine ran hot and low.
Not sure the generator can carry the load?Generator Wattage Calculator Running watts, the largest starting surge, and a generator class from manufacturer charts.Frequently asked questions
Can I add regular car oil to my Generac to clear a 1300?
In a pinch, an oil of the grade your manual specifies (synthetic 5W-30 per the 2016, 2017 and 2020 manuals) meeting API SJ/SL or better will get you through an outage. Generac's current manual specifies its own 5W-20 GEO oil after break-in, and using it keeps warranty questions simple.
How often should the oil be changed on a Generac standby?
Per the owner's manual: first change at 25 hours, then every two years or 200 hours of running, whichever comes first. Air filter, spark plugs, and valve clearance are every four years or 400 hours.
Does the low oil pressure switch shut the unit down instantly?
Generac does not publish the delay for current air-cooled units, so no figure is given here. What its article does say is that the shutdown follows the sensor, and that the owner's response is the same either way: let the engine cool for 30 minutes, then read the dipstick before touching anything else.
My oil is full but the alarm keeps coming back. Is the sensor bad?
Possibly, but the wiring to the sensor, a collapsing filter and genuine low pressure all look identical from the panel. Generac's instruction for a correct oil level with a repeat alarm is to contact a dealer, and the reason is that telling those three apart needs a mechanical gauge on a running engine.
Will the generator restart on its own after a 1300?
No. Alarms latch. You (or the dealer) must clear it at the panel before it will respond to an outage.
Parts and consumables
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Use the grade your manual's year specifies; the 2023 manual moved to Generac's 5W-20 GEO oil after break-in.
- Generac 5W-20 gaseous engine oil (GEO), 2-quartFind on Amazon
- Generac oil filter 070185ESFind on Amazon