What causes a SPN 3891 code?

SPN 3891 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 3891 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3891 active.

How do I fix SPN 3891?

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 3891

J1939 SPN 3891 — Body/Chassis parameter

What it means

J1939 SPN 3891: Body/Chassis Parameter. This code indicates a configuration mismatch, a time-out, or missing signal from the chassis-side module on the high-speed data link.