What is the voltage of the two wires on the car's charcoal canister solenoid valve?
2 Answers
The voltage of the two wires on the car's charcoal canister solenoid valve is 12 volts. The specific introduction is as follows: 1. Working principle: The working principle of the charcoal canister solenoid valve is that the purge solenoid valve controls the purification function of the charcoal canister through pulse width modulation. That is to say, the ECU computer turns the grounding circuit of the solenoid valve on or off at a certain frequency according to different operating conditions of the engine. The ECU computer controls the vacuum of the purge charcoal canister by operating a normally closed solenoid valve. 2. Precautions: The charcoal canister absorbs the oil vapor volatilized from the fuel tank to prevent the oil vapor from entering the atmosphere and polluting the environment. The function of the charcoal canister solenoid valve is to open when the oil vapor in the charcoal canister reaches a certain amount, allowing the oil vapor to enter the engine for combustion and reuse.
I've been tinkering with my old car lately, and the two wires on the charcoal canister purge valve have been quite problematic. The normal voltage should be around 12 volts. Generally speaking, one wire is the power supply line, coming directly from the car battery, maintaining a constant 12V DC in the normally open state. The other wire is the control line, connected to the engine control unit (ECU), which uses a pulse-width modulation signal to control the valve's opening and closing. It usually reads 0 volts, but when the engine warms up or during acceleration, the ECU sends pulse signals, causing the voltage to fluctuate between 5-12 volts. For testing, you can use a multimeter by connecting the ground wire and test points. If the voltage is unstable, the valve might be stuck, leading to a spike in fuel consumption or emission faults. I've experienced this myself—replacing the valve solved the issue. During regular maintenance, always check if the connectors are loose or corroded.
