What causes a SPN 324 code?

SPN 324 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 324 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 324 active.

How do I fix SPN 324?

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 324

J1939 SPN 324 — Fuel/Air parameter

What it means

Particulate Trap Secondary Fuel Injection Valve (Hydrocarbon Injector) circuit fault. This indicates the ECM has detected an electrical issue with the valve that controls fuel delivery for DPF regeneration.