What causes a SPN 3056 code?

SPN 3056 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 3056 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3056 active.

How do I fix SPN 3056?

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 3056

SPN 3056 Aftertreatment 1 SCR Catalyst Heat Output 1 High Current

What it means

The Engine Control Module (ECM) or Aftertreatment Control Module (ACM) detects an electrical current draw that exceeds the calibrated threshold for the Selective Catalytic Reduction (SCR) heating system.