How to Determine if a Solenoid Valve is Good or Bad?
2 Answers
Here are the methods for determining the condition of a solenoid valve: 1. Live check of the coil: When the solenoid valve coil is energized, it will generate heat. You can touch the coil to feel if there is any temperature. Since the energized coil produces magnetic force, you can use a metal object to check if there is any attraction inside the coil. 2. Dead check of the coil: You can use a multimeter to measure its resistance. Based on the resistance value, you can determine whether the coil is in good condition or if there is an open or short circuit situation. To check if the power supply meets the requirements, use a multimeter to measure the power supply voltage. Solenoid valves can be powered by 220V AC or 24V DC, so make sure to select the appropriate measurement based on the coil voltage specification.
Over the years I've been repairing cars, the simplest way to diagnose a solenoid valve boils down to three steps: First, feel for vibration when it's operating, then listen closely for the clicking sound of engagement. If both are absent, directly measure the coil resistance with a multimeter. Typically, gasoline car solenoids have a resistance between 15-25 ohms. An infinite reading indicates a broken coil, while abnormally low resistance suggests inter-turn short circuits. Just last week, I encountered a Hyundai with unstable idle – turned out to be a stuck purge valve. Interestingly, the engine smoothed out immediately when I unplugged it. Fundamentally, car solenoids operate like electrically controlled faucet valves. When they seize or leak, trouble follows. Turbocharged vehicles' blow-off valves are especially prone to carbon buildup. Never ignore a faulty solenoid – one client's transmission locked gears due to solenoid failure, resulting in tow truck fees triple the part's cost.