What causes a SPN 325 code?

SPN 325 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 325 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 325 active.

How do I fix SPN 325?

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 325

J1939 SPN 325 — Fuel/Air parameter

What it means

J1939 SPN 325 is a network communication diagnostic indicating an invalid or abnormal 'Fuel/Air' parameter received over the data link.