What causes a SPN 4701 code?

SPN 4701 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 4701 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4701 active.

How do I fix SPN 4701?

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 4701

Allison transmission code P4701

What it means

Allison P4701: Solenoid K2 Latch - Valve Stuck Off. This indicates the TCM has commanded the K2 solenoid to engage a clutch, but the expected pressure or gear ratio change was not detected.