How to Determine if a Solenoid Valve is Good or Bad?
2 Answers
Methods to determine if a solenoid valve is good or bad: 1. Unplug the solenoid valve's connector. If the suction phenomenon stops, it indicates the solenoid valve is functioning normally. If suction continues, it means the solenoid valve is stuck in the open state. 2. Start the engine and let it idle. Remove the pipe connected to the fuel tank. You should feel a suction phenomenon at the carbon canister's connector, with a frequency of about two to three times per second. If there is no suction, it indicates the solenoid valve is stuck in the closed state. A solenoid valve is an electromagnetically controlled industrial device used as an automated basic component for controlling fluids, acting as an actuator, and is not limited to hydraulic or pneumatic systems. Solenoid valves are categorized into three main types based on their operating principles: direct-acting solenoid valves, step-by-step direct-acting solenoid valves, and pilot-operated solenoid valves.
Once at the repair shop, I saw a mechanic testing a solenoid valve like this: first unplug the connector, set the multimeter to the resistance measurement mode, and touch the probes to the two metal contacts of the solenoid valve. A normal solenoid coil should have a resistance between 20 to 60 ohms. If the reading shows infinite resistance, it means the coil is completely open. Then, connect a 12V battery to simulate power supply—a clicking sound indicates the valve core is functioning properly. If there's no response and it heats up, it's likely broken. For valve bodies with oil leaks, the seals need extra inspection. The shift solenoid valve on the transmission is most prone to sticking, so when experiencing gear shift hesitation, it should be checked first. If unsure, the most reliable method is to test by replacing it with a new part.
