What causes a P0784 code?

P0784 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 P0784 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0784 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

P0784

P0784 - 4-5 Shift Malfunction (Heavy Duty Transmission)

What it means

Indicates a failure in the transmission control system to successfully execute or complete the gear change sequence between 4th and 5th gear.