What causes a SPN 424 code?

SPN 424 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 424 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 424 active.

How do I fix SPN 424?

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 424

J1939 SPN 424 — Fuel/Air parameter

What it means

SPN 424 is a general parameter code indicating an imbalance or out-of-range condition in the Fuel/Air ratio management, often relating to boost pressure or intake air volume versus fuel delivery.