What causes a SPN 345 code?

SPN 345 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 345 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 345 active.

How do I fix SPN 345?

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 345

J1939 SPN 345 — Fuel/Air parameter

What it means

SPN 345 indicates a communication or data validity error regarding the Fuel/Air parameters across the J1939 data link. This is generally a network integrity issue rather than a mechanical failure of the fuel system itself.