What causes a SPN 3957 code?

SPN 3957 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 3957 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3957 active.

How do I fix SPN 3957?

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 3957

J1939 SPN 3957 — Body/Chassis parameter

What it means

J1939 SPN 3957 indicates a fault related to Body/Chassis parameters, often involving the communication or signal validity of equipment added by the body builder (e.g., dump beds, cranes, lift gates) or the interface between the chassis and body controller.