What causes a SPN 3960 code?

SPN 3960 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 3960 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3960 active.

How do I fix SPN 3960?

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 3960

J1939 SPN 3960 — Body/Chassis parameter

What it means

SPN 3960 relates to abnormal data or electrical signals from the Body/Chassis parameter group. It often indicates the vehicle controller cannot interpret specific body-builder data or chassis-interface signals.