What causes a SPN 366 code?

SPN 366 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a SPN 366 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 366 active.

How do I fix SPN 366?

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

J1939 SPN

SPN 366

J1939 SPN 366 — Fuel/Air parameter

What it means

SPN 366 typically refers to a Fuel Injection Pump Speed/Position Sensor signal error, indicating a mismatch or loss of signal from the high-pressure fuel pump to the Engine Control Module.