What causes a SPN 815 code?

SPN 815 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 815 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 815 active.

How do I fix SPN 815?

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 815

J1939 SPN 815 — Engine Management parameter

What it means

Engine Management System (EMS) Power Supply sensing. This code indicates the ECM has detected an incorrect voltage level at the EMS power supply input.