There is no mechanical link between the accelerator pedal and the throttle plate. The accelerator pedal module at the pedal assembly communicates pedal position directly to the ECM, providing two variable voltage signals via Hall sensors for pedal position and rate of movement. The ECM supplies independent voltage and ground for each Hall sensor, with each receiving 5 volts and ground. As the accelerator pedal moves from rest to full throttle, the sensors generate a variable voltage signal. The output of the Hall sensors is checked for plausibility, with Hall sensor 1 ranging from approximately 0.5 to 4.5 volts and Hall sensor 2 from approximately 0.5 to 2.5 volts. The throttle housing unit is non-adjustable and should be replaced as a complete unit if found faulty. After replacement, a BMW scan tool or equivalent is needed to reset adaptation values, as failure to complete this process correctly will prevent the engine from starting. To replace the throttle housing, switch the ignition off and remove the key, then remove the air filter housing and ducts, followed by the charge air ducts. Disconnect the line at the side of the throttle assembly and the electrical connector underneath it, then remove the fasteners and the throttle housing. Installation is the reverse of removal, ensuring the throttle assembly connector is reattached carefully to avoid twisting, which can damage the harness and connector. Replace the profile gasket between the throttle assembly and intake manifold, and after reinstalling, check for fault codes and reset ECM memory, followed by resetting throttle plate adaptation values according to on-screen directions.
