What causes a SPN 1864 code?

SPN 1864 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 1864 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 1864 active.

How do I fix SPN 1864?

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 1864

SPN 1864 Clutch Actuator Position and Speed Synchronization Fault

What it means

Indicates a mechanical or electrical mismatch between the commanded clutch actuator position and the actual sensor feedback rate. This typically affects automated manual transmissions (AMT).