What causes a SPN 2828 code?

SPN 2828 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 2828 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 2828 active.

How do I fix SPN 2828?

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 2828

J1939 SPN 2828 — Aftertreatment/Emissions parameter

What it means

SCR Catalyst System Underefficiency - Efficiency Below Threshold. This code triggers when the SCR system detects that NOx reduction is not meeting the required percentage compared to the amount of DEF being injected.