What causes a SPN 3870 code?

SPN 3870 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 3870 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3870 active.

How do I fix SPN 3870?

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 3870

J1939 SPN 3870 — Body/Chassis parameter

What it means

Indicates a generic or specific fault within the body/chassis integration network. It often points to a sensor or communication issue related to body-builder equipment (dump beds, trash compactors, cranes).