What causes a SPN 3788 code?

SPN 3788 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 3788 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3788 active.

How do I fix SPN 3788?

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 3788

J1939 SPN 3788 — Body/Chassis parameter

What it means

Exhaust Gas Recirculation (EGR) Cooler Intake Pressure Sensor - Voltage Above Normal, or Shorted to High Source. Often interpreted as a Body/Chassis parameter mismatch regarding load or auxiliary status affecting engine derate logic.