What causes a SPN 3398 code?

SPN 3398 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 3398 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3398 active.

How do I fix SPN 3398?

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 3398

J1939 SPN 3398 — Body/Chassis parameter

What it means

This parameter represents the status or value of a specific body/chassis component (typically an auxiliary input) that is failing to transmit correctly over the J1939 network.