What causes a SPN 520950 code?

SPN 520950 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 520950 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 520950 active.

How do I fix SPN 520950?

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 520950

Air Pressure Sensor, Secondary (Tank) Circuit Fault

What it means

This code indicates an electrical fault in the secondary air tank pressure sensor circuit. This sensor provides critical information for brake system operation. The likely root cause is a faulty sensor or damaged wiring.