The BMW P0120 code is an indication of a malfunction in the throttle/pedal position sensor (A) circuit. This code is typically triggered when the engine starts and the temperature reaches 80 degrees Celsius while at idle (1320rpm). The throttle position sensor sends an implausible signal to the DME, and the throttle valve activation is performed by the electric motor (throttle drive) in the throttle valve control. There are several potential causes for this error code, such as a TP sensor signal circuit that is open or shorted to ground, a damaged or faulty TP sensor or module, a damaged or dirty throttle valve, or a faulty throttle valve control module. In order to remedy this code, it is important to identify the underlying cause and take the necessary corrective action.
TP Sensor Signal Circuit
The BMW P0120 code is caused when the throttle/pedal position sensor (A) circuit has an open or short to ground. The TP sensor circuit is responsible for sending a signal to the DME, which then activates the throttle valve through an electric motor (throttle drive). If the TP sensor circuit is faulty, the throttle valve will not open properly, and the engine will not run smoothly.
Damaged or Faulty TP Sensor
The BMW P0120 code can also be triggered if the TP sensor itself is damaged or faulty. The TP sensor is responsible for measuring the position of the throttle valve, and if it is not functioning properly, the DME will not be able to control the throttle valve properly. A damaged or faulty TP sensor can cause the engine to run rough and lop at idle, as well as cause a decrease in fuel economy.
Damaged or Dirty Throttle Valve
Another possible cause of the BMW P0120 code is a damaged or dirty throttle valve. The throttle valve is responsible for controlling the air-to-fuel ratio in the engine, and if it is damaged or dirty, it can cause the engine to run rough and lop at idle. A dirty or damaged throttle valve can also cause a decrease in fuel economy and can cause the engine to run lean or rich.
Faulty Throttle Valve Control Module
The BMW P0120 code can also be triggered if the throttle valve control module is faulty. The throttle valve control module is responsible for controlling the operation of the throttle valve, and if it is not functioning properly, the engine will not run smoothly.
Conclusion: Resolving the BMW P0120 Code
Resolving the BMW P0120 code requires identifying the underlying cause and taking the necessary corrective action. The code can be caused by an open or short to ground TP sensor circuit, a damaged or faulty TP sensor, a damaged or dirty throttle valve, or a faulty throttle valve control module. Once the underlying cause is identified, the necessary corrective action can be taken to remedy the BMW P0120 code and restore the engine to proper operation.
https://www.youtube.com/watch?v=tP-yinVw6zc