RPM Sense Signal Lost Due to Wiring Fault
The GENERAC-1116 (Generac Evolution) diesel fault code means: RPM Sense Signal Lost Due to Wiring Fault. This is a serious severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- moderate
- Estimated cost
- DIY sensor and connector repair: $25-$80 in parts. Professional diagnosis and MPU sensor replacement: $150-$350 labor plus parts. Controller board replacement if needed: $400-$700 installed.
A $30 car code reader can't do diesel. The HD7000 reads full-system codes and does parked DPF regen, idle/speed-limit, and service resets from the cab — on everything from a 6.7 Cummins/Power Stroke/Duramax pickup to Class-8 trucks (Detroit, Paccar, CAT, Volvo, Mack, International).
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Full-system 6/9/16-pin diesel scan tool for Cummins, Paccar, CAT, Detroit and more — plug-and-play, no subscription. A cheaper way to read heavy-duty codes a basic OBD2 scanner skips entirely.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Common Symptoms
- Generator displays code 1116 on the Evolution controller panel and shuts down
- Generator cranks normally but immediately shuts off within a few seconds of starting
- RUN light flashes or goes out shortly after crank attempt
- Generator fails its weekly exercise cycle and sits silent after attempting to start
- Red STOP light illuminates and alarm horn sounds after attempted start
- Generac Mobile Link or OnCue app reports a fault alert with code 1116
- Generator may crank repeatedly in failed start attempts before locking out
Probable Causes (Ranked by Likelihood)
- Broken, corroded, or unplugged magnetic pickup (MPU) sensor connector at the harness junction near the flywheel housing Very Likely
- Magnetic pickup sensor itself has failed, either from vibration damage, heat soak, or debris contact with the flywheel ring gear Very Likely
- Chafed or pinched wiring in the MPU harness run between the sensor and the Evolution controller board, causing an open or short circuit Likely
- Magnetic pickup air gap set too wide after an engine service, resulting in a signal too weak for the controller to read Likely
- Stator sense winding damaged or open-circuited, causing the controller to lose its secondary RPM reference signal Possible
- Corrosion or moisture intrusion at the main wiring harness connector on the Evolution controller board, degrading the RPM input signal Possible
- Evolution controller board input circuit for RPM sensing has failed internally Less Likely
Step-by-Step Diagnostic Procedure
Start at the panel. Press OFF, then hold the INFO or ENTER button to scroll fault history and confirm code 1116 is the active fault. Write down any companion codes showing alongside 1116.
Locate the magnetic pickup sensor. On most Generac OHVI and G-Force engines, it threads into the bellhousing or timing cover near the flywheel ring gear. Trace the two-wire pigtail from the sensor to its harness connector. Unplug it and inspect both pins for green corrosion, bent pins, or moisture. Clean with electrical contact cleaner and reconnect firmly.
With the connector unplugged, set your multimeter to AC millivolts. Have a helper briefly crank the engine from the panel (set to MANUAL, press START for just 2-3 seconds). A working MPU sensor will produce an AC voltage spike of roughly 0.5 to 5 volts AC as the ring gear teeth pass. No reading means a dead sensor or no continuity to it.
With the engine off and the ignition disabled, set your multimeter to resistance (ohms). Measure across the two terminals of the MPU sensor itself. A healthy Generac magnetic pickup typically reads between 150 and 1,000 ohms depending on model. An open reading (OL) or a dead-short reading near 0 ohms both indicate a failed sensor.
Inspect the air gap between the tip of the magnetic pickup and the ring gear teeth. With the sensor threaded in, it should be approximately 0.030 to 0.060 inches (about the thickness of two quarters stacked). If the gap is visibly large, the signal will be too weak. Turn the sensor in clockwise until it just contacts the ring gear, then back it out one full turn and lock the jam nut.
Trace the full length of the MPU harness from the sensor to the Evolution controller. Look for spots where the wire passes near hot exhaust components, sharp sheet metal edges, or moving parts. Flex the harness gently while watching for any intermittent signal on your multimeter. Any chafe through the insulation causes a fault.
Check the RPM input connector at the Evolution controller board itself. It is typically a small 2- or 4-pin Weather Pack connector on the main harness. Unplug it, inspect for corrosion or pushed-back terminals, reseat it firmly. If corrosion is heavy, use electrical contact cleaner and a terminal pick to clean the female sockets.
If the sensor, wiring, gap, and connectors all test good and the fault persists, the RPM input circuit on the Evolution controller board itself may be damaged. At this point the diagnosis requires a Generac Activator app and a trained technician to rule out a board replacement. Call a Generac dealer or certified service tech.
Frequently Asked Questions
What does Generac code 1116 mean?
Code 1116 means the Evolution controller tried to start the engine but never received a valid RPM signal from the magnetic pickup sensor or its wiring. The controller has no way to confirm the engine is actually running, so it shuts everything down immediately as a safety measure. The problem is almost always the sensor, its connector, or the wires between the sensor and the controller board.
Can my generator still run with code 1116?
No. The generator will crank but will shut down within seconds every time because the controller never sees a valid RPM signal. It will not produce power and will not protect your home during an outage until this fault is cleared.
How much does it cost to fix code 1116?
If the fix is a dirty or unplugged connector, it costs nothing but your time. A replacement magnetic pickup sensor typically runs $25 to $60 in parts and takes about an hour to swap. If the wiring harness needs repair or the Evolution controller board itself is damaged, a professional repair runs $150 to $700 depending on what needs replacing.
Will my generator start the next time the power goes out?
No. With code 1116 active, the generator will attempt to crank, fail to confirm engine speed, and shut itself down before it can transfer power to your home. You need to resolve this fault before you can rely on the generator for emergency backup power.