What causes a SPN 444 code?

SPN 444 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 444 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 444 active.

How do I fix SPN 444?

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 444

SPN 444 Fan Drive Source Identification

What it means

This fault indicates an issue with the engine cooling fan control circuit, specifically a fault or short in the fan drive relay or solenoid circuit.