How to Determine if a Solenoid Valve is Good or Bad?

[DeRachel]

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.

[MacArcher]

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.

[MacSarah]

As a technical supervisor mentoring apprentices, I often teach them to use pressure gauges for pipeline testing. For example, when inspecting transmission solenoid valves, first connect the oil pressure gauge and start the engine, then observe whether the pressure changes smoothly. During normal gear shifts, the oil pressure should rise and fall rhythmically. If the needle suddenly drops or remains completely still, there's a high chance the valve spool is stuck. I remember a BMW with rough shifting—when we activated the solenoid valve with the diagnostic tool, the pressure didn't budge at all. Upon disassembly, we found the valve body jammed with metal debris. Nowadays, newer vehicles mostly use PWM (pulse-width modulation) to control solenoid valves, so reading the actual opening value via the diagnostic tool is the most reliable method. For instance, in Volkswagen models, if the solenoid valve opening deviation in the data stream exceeds 5%, it indicates an abnormality. For vehicles experiencing poor acceleration, it's worth focusing on inspecting the turbocharger's wastegate valve.

[LeJulia]

Last time my neighbor's little sister's Fit had a warning light on, I taught her a simple trick: unplug the solenoid valve while the engine is warm. For parts like the charcoal canister solenoid valve, the engine will stabilize after disconnection. If unplugging it doesn't make any difference, it's basically confirmed to be faulty. This method also works for fuel injector solenoid valves - unplug them one by one at idle, and the one that causes the engine to stop shaking when unplugged is the faulty one. Solenoid valves in cars are actually like little speakers, making a clicking sound when powered. You can hear it clearly by placing a long screwdriver against them. Remember to check if the connector pins are dirty or oxidized. There was an old Regal that had signal short circuits due to water in the connectors.

[Kimberly]

When it comes to solenoid valve testing, I prefer using a 12V battery for direct wire testing. For instance, when checking the idle speed solenoid valve, you should hear a crisp clicking sound upon power connection, and feel slight vibration when touching the valve body – these indicate normal operation. Last year, I handled a classic case: a Cayenne with cold start issues. During fuel pressure solenoid valve inspection, I found the return line still leaking after power application, indicating valve seat seal failure. Actually, solenoid valve failures fall into two categories: either complete failure to move, or inability to seal properly causing air/oil leaks. Modified cars require special attention – excessive ECU tuning may burn out solenoid coils, like a tuned GTI that fried its turbocharger solenoid valve.