Diagnostic Overview
Mack fault code SPN52460 is commonly an aftertreatment inducement or emissions-system derate status code. It usually means the truck has reached an SCR/DEF or aftertreatment warning level because another emissions fault has not been corrected. This is often a result code, not the original root cause.
Likely Causes
Unresolved DEF/SCR code; poor DEF quality; failed NOx sensor; DEF dosing failure; DPF restriction; aftertreatment communication fault.
What To Check First
Scan all active codes and diagnose the root aftertreatment fault first. After repair, complete the required reset, regen, or confirmation drive cycle.