What causes a SPN 379 code?

SPN 379 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 379 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 379 active.

How do I fix SPN 379?

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 379

J1939 SPN 379 — Fuel/Air parameter

What it means

SPN 379 indicates an 'Aftertreatment Fuel Air Pressure' issue, specifically that the air pressure used to atomize fuel in the exhaust stream for DPF regeneration is out of the expected range.