What causes a U3271 code?

U3271 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 U3271 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U3271 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

Log in Sign up

OBD-II

U3271

Manufacturer-specific network code U3271

What it means

Loss of communication between the Primary Control Module and the Secondary/Slave module (Dual ECU setups).

Sign in to view symptoms, probable causes, diagnostic steps, severity, and related codes

Log in Sign up free