What causes a SPN 2992 code?

SPN 2992 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 2992 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 2992 active.

How do I fix SPN 2992?

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 2992

J1939 SPN 2992 — Aftertreatment/Emissions parameter

What it means

SPN 2992 refers to Aftertreatment 1 SCR Intake Temperature or related NOx conversion efficiency metrics depending on the specific model. Use of this code typically indicates the engine ECM is receiving invalid or out-of-range emissions data from the SCR system.