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Home >> Cadillac >> 2020 >> CT6 V >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 4.2L (LTA) - Diagnostic Information And Procedures (2 Of 2) >> Diagnostic Information And Procedures >> DTC P2AB8, P2AB9, P2ABB, P2ABC, P2B81, P2B82, P2B93, P2B94, U0644, U0674, U1376, or U1377 >> Circuit/System Description
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Circuit/System Description

For an overview of the component/system, refer to:Compressor Air Intake Turbocharger System Description

Circuit Description
5 V Reference Regulated voltage supplied by the control module.
Serial Data The control module input circuit has an internal resistance connected to 5 V.
Digitally encoded information for communication between devices.
Low Reference Grounded through the control module.
Component Description
K20 Engine Control Module The control module contains a microprocessor used to process input data to control outputs.
The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
M128 Turbocharger Wastegate Actuator The assembly has several functions:
  • The valve is actuated by a DC motor. A spring is used to keep the valve in the open position. The valve actuator motor moves the valve in the closed direction. The more current flows through the motor, the more the valve closes.
  • The component M128 contains a contactless inductive position sensor. A fixed transmitter coil excites a movable rotor, which in turn induces a current in a fixed receiver coil. The current varies with the angle of the rotor. Electronics inside the sensor convert the current into digital data which is transmitted via a serial data circuit to the control module K20.