What causes a SPN 4407 code?

SPN 4407 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 4407 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4407 active.

How do I fix SPN 4407?

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 4407

Allison transmission code P4407

What it means

P4407 (SPN 4407) is an Allison Generation 4/5/6 diagnostic code indicating a 'Software Revision Level Mismatch' or a 'Processor Fault'. It typically suggests the TCM has detected an internal logic error or a checksum failure between stored parameters and the active software.