What causes a SPN 279 code?

SPN 279 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 279 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 279 active.

How do I fix SPN 279?

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 279

J1939 SPN 279 — Fuel/Air parameter

What it means

SPN 279 is a general parameter for Intake Manifold or Ambient Air Temperature, often indicating that the temperature reading is out of range or inconsistent with other sensor readings (rationality fault).