Oil Pressure Sensor Signal Voltage Above Normal Range
What does PERKINS-100-3 mean?
The PERKINS-100-3 (Kohler RDC2) diesel fault code means: Oil Pressure Sensor Signal Voltage Above Normal Range. This is a serious severity code.
Common Symptoms
- Panel displays fault code 100-3 or shows an oil pressure sensor warning
- Yellow or red alarm light illuminates on the controller panel
- Generator shuts down or refuses to start due to a sensor fault
- Oil pressure gauge on the panel reads unusually high or pegged at maximum
- PowerWizard 1.1 or 2.0 display shows 'Oil Press Voltage High' in the fault log
- Engine may crank but immediately trips on a sensor-related shutdown
- No actual oil pressure loss observed when you check the oil level and condition manually
Probable Causes (Ranked by Likelihood)
- Open circuit in the oil pressure sensor wiring harness, causing the signal wire to float high Very Likely
- Oil pressure sensor signal wire shorted to a 5V reference or battery positive wire Very Likely
- Failed oil pressure sensor with internal open circuit driving voltage above the acceptable range Likely
- Corroded or backed-out connector pin at the sensor or ECM harness plug Likely
- Damaged wiring insulation causing intermittent contact with a higher-voltage circuit Possible
- ECM or PowerWizard controller internal fault affecting the sensor input channel Less Likely
Step-by-Step Diagnostic Procedure
Step 1. Set the panel switch to OFF and let the engine cool for at least 5 minutes. Locate the oil pressure sensor on the engine block, typically near the oil filter on the 1103D, 1104D, and 1106D series. On larger engines like the 2206D and 2506D, check the left-hand side of the block near the oil cooler.
Step 2. Visually inspect the sensor connector and wiring harness. Look for broken wires, melted insulation, corrosion inside the connector pins, or any wire that has rubbed against a hot surface or moving part.
Step 3. Disconnect the sensor connector. Set your multimeter to DC voltage and measure from the signal pin in the harness connector to engine ground. With the ignition key or panel in the RUN position but the engine not cranking, you should see approximately 0.5V to 4.5V. A reading at or above 4.8V with the sensor disconnected confirms an open-circuit condition in the harness or a wiring short to power.
Step 4. With the sensor still disconnected, measure resistance from the signal wire pin in the harness back to the ECM sensor-return pin. A reading of infinite ohms (OL on your meter) confirms a broken wire. A reading under 5 ohms confirms continuity is intact and the sensor itself is the likely fault.
Step 5. If the harness checks out, reconnect the sensor and measure DC voltage directly at the sensor signal pin while a second person holds the panel in RUN (do not start the engine). A voltage above 4.8V with the sensor connected and engine off points to a failed sensor. Typical spec for Perkins pressure sensors at zero pressure is roughly 0.5V.
Step 6. Inspect the ECM or controller harness plug for bent or pushed-back pins. Push each pin gently to confirm it is seated. Spray electrical contact cleaner into the connector and reconnect it. Clear the fault using PowerWizard 1.1 or 2.0, or with Perkins EST if available, and attempt a test start.
Step 7. If the fault returns immediately after clearing and the wiring checks clean, replace the oil pressure sensor. This is a standard Perkins sensor available through FG Wilson dealers. After replacement, clear the code and confirm the reading on the PowerWizard display shows a plausible pressure value (around 40 to 70 PSI at idle on most Perkins genset engines).
Step 8. If replacing the sensor and repairing visible wiring does not clear the fault, the ECM sensor input circuit may be damaged. At this point, call a Perkins or FG Wilson certified technician with Perkins EST to run a full pin-out test on the ECM harness.
Frequently Asked Questions
What does Perkins code 100-3 mean?
It means the controller measured a voltage on the oil pressure sensor signal wire that is higher than the sensor should ever produce. This usually means there is a broken wire, a bad connector, or a failed sensor rather than an actual oil pressure problem. The controller cannot tell the difference between 'sensor broken' and 'real danger,' so it shuts the generator down to protect the engine.
Can my generator still run with this code?
No. Code 100-3 is treated as a protective shutdown on Perkins genset controllers. The generator will refuse to start or will shut down shortly after cranking until the fault is cleared. Do not try to bypass this protection, since an actual oil pressure loss would destroy the engine.
How much does it cost to fix?
If the fault is just a failed sensor, you are looking at $40 to $120 for the part and about an hour of your time if you are comfortable with basic electrical work. If a shop diagnoses and replaces it, expect $150 to $300 total. A wiring harness repair by a technician could push the cost to $400 or more depending on how much of the harness is damaged.
Will the generator start the next time the power goes out?
Not until the fault is cleared. Perkins controllers with PowerWizard 1.1 or 2.0 will block an automatic start when fault code 100-3 is active. If you depend on this generator for backup power, treat this as an urgent repair. After fixing the root cause, you must clear the fault code using the controller or Perkins EST before the unit will respond to an AUTO start signal.