What causes a SPN 90 code?

SPN 90 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 90 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 90 active.

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 90

J1939 SPN 90 — Engine parameter

What it means

SPN 90 indicates a fault with the Accelerator Pedal Position (APP) signal, specifically related to the sensor that measures how far the driver is pressing the pedal.