What causes a SPN 1138 code?

SPN 1138 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 1138 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 1138 active.

How do I fix SPN 1138?

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 1138

Engine Exhaust Pyrometer 2 Temperature

What it means

Measures the temperature of the exhaust gas at the second pyrometer location.

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

Log in Sign up free