Caterpillar Fault Code
Free · no signupSPN 94 FMI 3
Engine "stumble" under load; Hard starting; Low power.
System
Not specified
Symptom
Engine "stumble" under load; Hard starting; Low power.
Diagnosis & fix steps
Fuel Delivery Pressure High (Voltage).
LOGIC: Signal > 4.5V (Open Circuit). Without this signal, the ECM can't adjust the transfer pump or timing for fuel density.
ACTION: 1. Perform "Bypass Test" (Jumper pins). If code changes to FMI 4, sensor is dead.
2. Inspect connector for "pin fret" (vibration wear).
FIX: Replace Fuel Pressure Sensor or repair broken signal wire.
Red Seal field insights
On many CAT C-series engines, this sensor is identical to the Oil Pressure sensor. You can swap them for testing purposes to see if the fault follows the sensor.
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