What causes a U0891 code?

U0891 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 U0891 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U0891 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

U0891

Network/CAN bus communication code U0891

What it means

CAN network fault regarding a lack of synchronization between the Powertrain Control Module and the Braking System.

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

Log in Sign up free