What causes a SPN 374 code?

SPN 374 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 374 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 374 active.

How do I fix SPN 374?

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 374

J1939 SPN 374 — Fuel/Air parameter

What it means

SPN 374 is a generic J1939 fault indicating a deviation or error in the expected Fuel/Air parameter, often relating to the fuel pressure regulator or fuel rail pressure sensor signals.