What causes a SPN 521047 code?

SPN 521047 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 521047 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 521047 active.

How do I fix SPN 521047?

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 521047

SPN 521047 FMI 7 - VGT Actuator Position Drift/Overtemperature

What it means

This fault indicates that the Variable Geometry Turbocharger (VGT) actuator has failed to reach its commanded position or has detected a mechanical blockage, commonly on Mack MP series engines.