What causes a SPN 3684 code?

SPN 3684 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 3684 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3684 active.

How do I fix SPN 3684?

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 3684

J1939 SPN 3684 — Body/Chassis parameter

What it means

Particulate Trap Inlet Pressure Sensor - Data Erratic/Intermittent/Incorrect. Indicates a calibration or signal mapping error between the BCM and Engine Controller regarding atmospheric or inlet pressure.