What causes a SPN 3857 code?

SPN 3857 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 3857 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3857 active.

How do I fix SPN 3857?

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 3857

J1939 SPN 3857 — Body/Chassis parameter

What it means

SPN 3857 relates to a Body/Chassis parameter mismatch or communication error where the vehicle configuration does not match the expected input from the body controller or body builder interface.