GENERAC-1505 serious Generac Evolution ›

RPM Sensor Loss: No Valid Engine Speed Signal (Generac 1500-1522 Family)

The GENERAC-1505 (Generac Evolution) diesel fault code means: RPM Sensor Loss: No Valid Engine Speed Signal (Generac 1500-1522 Family). This is a serious severity code.

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Keep running?
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DIY difficulty
moderate
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What Are the Symptoms of GENERAC-1505?

  • The generator fails to start, or shuts down unexpectedly while running, with a red light
  • Mobile Link: "The generator has experienced a no crank RPM Sensor alarm. Please contact a dealer."

What Causes GENERAC-1505? (Most Likely First)

  • Weak or bad battery Likely
  • Fuel system problem Possible
  • Overload or a sudden change in load Possible
  • Missed routine maintenance Possible

Can I Keep Running It with GENERAC-1505?

No — shut it down. GENERAC-1505 is rated serious severity. Continuing to run the unit in this state risks further damage — get it looked at before putting it back in service.

Common Fixes by Vehicle

What techs usually find when diagnosing GENERAC-1505 on specific platforms — tap a platform for the fix and the exact part:

Generac Evolution 2.0 controllers (2013+ Guardian) Moderate DIY

Code 1505 (RPM Sense Loss) usually comes from the magnetic pickup at the flywheel rather than the controller. Pull the pickup, inspect the tip for metal debris (clean with a magnet and rag), and check the gap to the flywheel teeth (0.030 in spec on most platforms). Replace if the coil reads open or the tip is damaged. If the pickup tests fine, suspect the harness pin at the controller connector -- backed-out terminals are common.

Labor: 30-45 min
Common fix part Generac Magnetic Pickup Sensor View on Amazon→ Compare fitment at PartsGeek→

Frequently Asked Questions

What does Generac code 1505 mean?

RPM sensor loss: the controller did not see a valid engine speed signal at startup, or lost it while running. Generac says owner troubleshooting is the same for every code in the range. Generac groups 1500-1522 under one alarm and does not publish a separate meaning for 1505.

Is it always the sensor?

No. Generac lists a weak battery, fuel problems, overload or a sudden load change, and missed maintenance as potential causes.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose GENERAC-1505?

  1. Note when it happened: Generac troubleshoots a failure to start differently from a shutdown while running.

  2. If it happened when starting, check the battery, battery terminals and cables. Generac notes home standby batteries last 3-5 years on average.

  3. Clear the alarm and restart: on Evolution controllers press OFF, ENTER twice, then AUTO; on Power Zone 200 controllers hold OFF for 3 seconds. Never start the generator while it is under load.

  4. If the code comes back after clearing it, Generac recommends a Generac Independent Authorized Service Dealer (IASD).

Sources 2

This page is built from documented references. Verify against your own service info before repair work.

Which Vehicles Commonly Get GENERAC-1505?

  • Generac air-cooled home standby generators (Guardian and Next Generation series)
  • Evolution controllers show the code on the display; Power Zone 200 controllers show it in Mobile Link

Explore More

More Generac Evolution codes → Diesel home All diesel codes Heavy-duty Guides

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