What causes a U0733 code?

U0733 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 U0733 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U0733 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

U0733

Network/CAN bus communication code U0733

What it means

Engine Protection/Electronic Fan Control communication failure. The cooling fan controller is not communicating with the ECM.

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

Log in Sign up free