The throttle valve plate is electronically operated by the ECM to regulate intake air flow, with the EDK motor being pulse width modulated by the ECM to open and close the throttle plate, which is also closed by a fail-safe return spring. Two integrated potentiometers in the EDK housing provide feedback to the ECM for throttle plate angle during operation. The throttle housing unit (EDK) is nonadjustable and must be replaced as a complete unit if found faulty. After replacement, the adaptation values must be reset using a BMW scan tool. To begin, switch the ignition off and remove the key, then remove the air filter housing and air intake ducts. Working at the side of the
Intake Manifold, disconnect electrical connectors for the intake manifold resonance valve and idle speed control valve, as well as the oil pressure and oil temperature sender connectors at the base of the oil filter housing. At the left side and underneath the intake manifold, detach the electrical connector at the fuel tank venting valve and disconnect the hose at the quick disconnect fitting before removing the valve from the manifold. Remove the wiring harness housing mounting fasteners and pull the housing away from the throttle assembly, then remove the engine oil dipstick tube. At the throttle housing, unscrew the harness plug counterclockwise to disconnect it, then remove the throttle housing mounting fasteners and pull the assembly off the manifold. Installation is the reverse of removal, ensuring to replace the profile gasket (sealing O-ring) between the throttle assembly and intake manifold, and reattach the throttle assembly connector carefully, aligning the arrows on the connector and housing. Finally, use the BMW scan tool to check and clear fault codes from the ECM memory and reset the throttle adaptation values, noting that if the adaptation process is not completed correctly, the engine will not start.