What causes a SPN 3493 code?

SPN 3493 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 3493 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3493 active.

How do I fix SPN 3493?

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 3493

J1939 SPN 3493 — Body/Chassis parameter

What it means

Aftertreatment 1 Rear SCR Catalyst Temperature - Abnormal Rate of Change (specific to some chassis wiring configurations, this SPN is most commonly mapped to the Aftertreatment / Backup Alarm Output circuit in heavy-duty J1939 applications).