What causes a SPN 384 code?

SPN 384 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 384 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 384 active.

How do I fix SPN 384?

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 384

J1939 SPN 384 — Fuel/Air parameter

What it means

Intake Air Heater (IAH) Relay Control Circuit. This code indicates a malfunction in the electrical circuit that controls the pre-heater used to warm air entering the cylinders.