What causes a SPN 3255 code?

SPN 3255 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 3255 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3255 active.

How do I fix SPN 3255?

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 3255

SPN 3255 - Aftertreatment 1 Intake Temperature Sensor High

What it means

Indicates that the exhaust gas temperature at the inlet of the Diesel Oxidation Catalyst (DOC) is above the maximum acceptable operating range.