P0243 Code 5.9 Cummins


This code is applicable to 3rd Gen model year 04.5-07 5.9 Cummins trucks.  It is typically caused when an aftermarket turbo is installed that does not have an electronic wastegate.  This results in the factory wastegate harness getting unplugged and typically left hanging.  The ECM will sense the lack of continuity on the circuit and set code P0243 and illuminate the check engine light.

The proper solution is to purchase a wastegate (NOT a boost fooler, they are two separate things) and plug it into the factory harness, then reset your DTC codes.

You can purchase a wastegate fooler here:


See my tuning in action…

High Altitude 12 Valve Tune Cold Start

An early version of my towing tune…