What causes a SPN 746 code?

SPN 746 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 746 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 746 active.

How do I fix SPN 746?

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 746

J1939 SPN 746 — Engine Management parameter

What it means

SPN 746 typically refers to a fault in the Differential Lock Solenoid circuit (often the Axle Differential Lock Control). It indicates the controller has detected an electrical discontinuity or short in the solenoid circuit.