What causes a SPN 4804 code?

SPN 4804 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 4804 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4804 active.

How do I fix SPN 4804?

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 4804

Allison transmission code P4804

What it means

Solenoid Return Current Too Low. This code indicates that the TCM has detected an open circuit or high resistance on the common return line for the transmission solenoids.