What causes a SPN 703 code?

SPN 703 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 703 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 703 active.

How do I fix SPN 703?

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 703

J1939 SPN 703 — Engine Management parameter

What it means

SPN 703: Auxiliary Output / Engine Shutdown Switch. This indicates the Engine Control Module has received a request from an external device or switch to override engine operation or shut down.