What causes a SPN 331 code?

SPN 331 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 331 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 331 active.

How do I fix SPN 331?

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 331

J1939 SPN 331 — Fuel/Air parameter

What it means

SPN 331 is a general parameter identification for Fuel/Air feedback, typically indicating that the engine controller is detecting a value from its air or fuel pressure sensors that is out of the expected operational range or logically inconsistent with other sensor inputs.