What causes a SPN 849 code?

SPN 849 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 849 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 849 active.

How do I fix SPN 849?

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 849

J1939 SPN 849 — Engine Management parameter

What it means

Wheel Based Vehicle Speed. Indicates an error in the wheel speed data received via the J1939 datalink or a configuration mismatch in the Engine Management system.