What causes a SPN 4356 code?

SPN 4356 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 4356 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4356 active.

How do I fix SPN 4356?

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 4356

SCR Line Heater #3

What it means

SCR Line Heater #3 refers to the heater element for the DEF suction line (from the tank to the pump). The Aftertreatment Control Module (ACM) has detected an electrically incorrect signal (open or short).