What causes a SPN 3074 code?

SPN 3074 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 3074 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3074 active.

How do I fix SPN 3074?

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 3074

SPN 3074 - Engine Cylinder Pressure Relief Valve Actuator Circuit

What it means

Indicates an electrical fault or out-of-range signal from the cylinder pressure relief valve actuator, typically used for engine braking or advanced combustion control.