A component designed to alter the pressure reading relayed by the manifold absolute pressure sensor on an L5P Duramax diesel engine. It essentially shifts the sensor’s position relative to the intake manifold, creating a change in the pressure detected. As an example, installing this device may cause the engine control unit to perceive a lower boost pressure than is actually present in the intake manifold.
This modification is frequently employed to address issues arising from increased turbocharger output. Elevated boost pressures, beyond the factory-calibrated range, can sometimes trigger diagnostic trouble codes or limit engine performance. Altering the sensor’s reading can, in some instances, circumvent these limitations, potentially optimizing engine performance under modified conditions. The device’s origin lies within the diesel performance aftermarket, as a means of fine-tuning engine behavior in applications that deviate from stock configurations.