What causes a SPN 2803 code?

SPN 2803 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 2803 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 2803 active.

How do I fix SPN 2803?

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 2803

SPN 2803 Transmission Output Shaft Speed Sensor

What it means

The Engine Control Module (ECM) or Transmission Control Module (TCM) has detected an invalid or erratic signal from the transmission output shaft speed sensor via the J1939 data link.