What causes a SPN 3249 code?

SPN 3249 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 3249 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3249 active.

How do I fix SPN 3249?

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 3249

SPN 3249: Aftertreatment 1 Intake Temperature Sensor High

What it means

This code indicates the temperature of the exhaust gas entering the Diesel Particulate Filter (DPF) has exceeded the normal operating range or is reading out of range.