What causes a SPN 523502 code?

SPN 523502 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 523502 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 523502 active.

How do I fix SPN 523502?

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 523502

Axle Speed Sensor Input Fault

What it means

This code indicates an issue with an axle speed sensor, which monitors the rotation of the axle for various control systems. Incorrect data can affect ABS, traction control, and transmission shifting. The likely root cause is a faulty sensor, wiring, or tone ring.