What causes a SPN 745 code?

SPN 745 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 SPN 745 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 745 active.

How do I fix SPN 745?

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

J1939 SPN

SPN 745

J1939 SPN 745 — Engine Management parameter

What it means

SPN 745 usually refers to an electrical fault within the Engine Brake Solenoid 1 circuit. This is the actuator responsible for controlling the compression release engine brake (Jake Brake) on one bank of cylinders.