What causes a SPN 2108 code?

SPN 2108 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 2108 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 2108 active.

How do I fix SPN 2108?

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

Log in Sign up

J1939 SPN

SPN 2108

Transmission Reverse Switch Status Missing

What it means

Reverse gear status signal is not being received correctly by other modules.

Sign in to view symptoms, probable causes, diagnostic steps, severity, and related codes

Log in Sign up free