What causes a SPN 1503 code?

SPN 1503 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 1503 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 1503 active.

How do I fix SPN 1503?

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

Log in Sign up

J1939 SPN

SPN 1503

Internal Memory Fault

What it means

Reports a checksum error or failure in the non-volatile memory of the electronic control unit.

Sign in to view symptoms, probable causes, diagnostic steps, severity, and related codes

Log in Sign up free