Circuit/System Description

The Cylinder Deactivation System Performance diagnostic is a test of the internal mechanical condition of the engine, during operation in V4 mode. The engine control module (ECM) determines the internal mechanical condition of the engine through the actual measured values of the mass airflow (MAF) sensor, the intake manifold absolute pressure (MAP) sensor, and the throttle position (TP) sensor. The actual measured values of the 3 sensors are then compared to the calculated values for V4 mode, stored in the ECM. If the measured values are incorrect for V4 mode, the ECM will set DTC P3400, and will return to V8 mode operation.