P2108 BMW Throttle Actuator Control Module Problem
– Throttle Actuator Control Module circuit poor electrical connection
– Check throttle body for binding-Clean throttle body
– Throttle body actuator malfunction
– Defective throttle body
– Engine hard to start
– Rough or erratic idle speed
The electronic throttle control system controls the throttle valve opening. The system is composed of the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the throttle actuator control module, the throttle actuator control module relay, the accelerator pedal position (APP) sensor, and the engine control module (ECM)/powertrain control module (PCM).
The APP sensor is operated via the throttle cable to determine the accelerator opening value when the driver presses the accelerator pedal. The accelerator pedal opening value is converted to a signal in the APP sensor and transmitted to the ECM/PCM to compute the target position. The target position signal is then transmitted to the throttle actuator control module.
The throttle actuator control module determines the throttle valve target position according to the signal received and operates the throttle actuator to move the throttle valve to the target position. The actual throttle valve position is determined by TP sensor A installed in the throttle body.
The throttle actuator control module compares the throttle valve target opening angle and the actual throttle valve opening angle from TP sensor A, and when the difference exceeds the specification, the throttle actuator control module transmits the malfunction data to the ECM/PCM. When the ECM/PCM receives the malfunction data from the throttle actuator control module,
the ECM/PCM detects the malfunction of the throttle actuator system and a DTC is stored.