What causes a SPN 5003 code?

SPN 5003 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 5003 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 5003 active.

How do I fix SPN 5003?

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 5003

Allison transmission code P5003

What it means

Transmission Control Module (TCM) internal fault or circuit monitoring error specifically related to internal relay or solenoid power supply circuits.