What are the symptoms of a faulty BMW solenoid valve?

[LeJuliette]

BMW solenoid valve damage manifests as unstable engine idle speed and weak acceleration. The engine is difficult to start because when the carbon canister solenoid valve remains open, the fuel tank and the engine intake manifold are directly connected. When parked, a large amount of gasoline vapor enters the intake manifold, making the air-fuel mixture too rich during engine startup, which makes it difficult to start. Below are the specific details about automotive air conditioning solenoid valves: 1. Components: The solenoid valve in the air conditioning system generally consists of an electromagnetic coil and a magnetic core, including one or more holes on the valve body (such as three-way valves for cooling and heating). When the coil is energized or de-energized, the core moves to control the valve body's opening and closing. The electromagnetic coil is directly installed on the valve body, and the magnetic core is enclosed in a sealed tube. 2. Working Principle: Air conditioning solenoid valves are usually directly connected, with specifications such as AC 220 volts, DC 24 volts, and a diameter generally ranging from 3-25 mm. When the air conditioning starts, the electromagnetic coil generates electromagnetic force to open the valve, initiating the refrigerant cycle. 3. Function: To reach the set temperature, the air conditioning solenoid valve coil is de-energized, the electromagnetic force disappears, and the refrigerant cycle is closed, thereby regulating the temperature.