What causes a SPN 5004 code?

SPN 5004 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 5004 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 5004 active.

How do I fix SPN 5004?

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 5004

Allison transmission code P5004

What it means

Solenoid Power Supply Voltage High / Internal Solenoid Power Supply Feedback Error. Usually indicates an internal fault in the TCM's ability to regulate or monitor power to the solenoids.