What causes a U3431 code?

U3431 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 U3431 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U3431 active.

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

OBD-II

U3431

Manufacturer-specific network code U3431

What it means

Lost communication with the Battery Management System (BMS) sensor. The truck cannot accurately monitor battery state of charge or health.