The static inspection method should be used to measure the solenoid valve coil with a multimeter.
The inspection and judgment methods of solenoid valves can be roughly divided into three types:
1. Static inspection of solenoid valve
Static inspection refers to measuring the resistance value of the solenoid valve when the ignition switch is OFF, connect the tip of a multimeter to the pin of the solenoid valve, and observe the resistance value displayed on the meter screen. If it is greater than the rated value, the solenoid valve coil is aging; if it is low The rated value indicates that there is a short circuit between the coil turns; if it is infinite, it indicates that the solenoid valve coil is open. These conditions indicate that the solenoid valve has failed and must be replaced.
2. Dynamic inspection of solenoid valve
Dynamic inspection refers to simulating the actual working process of the solenoid valve, replacing the oil pressure with a certain air pressure, and checking whether the spool movement of the solenoid valve is smooth and the sealing performance is good through continuous artificial excitation of the solenoid valve.
Use an air gun to apply a certain air pressure to the working oil hole of the solenoid valve through the cone-shaped rubber head, press the control switch to repeatedly turn on and off the solenoid valve, and observe the changes in the air flow at the drain port. If the air flow always exists, the solenoid Poor valve seal.
If there is no air flow, it means that the solenoid valve is blocked and stuck; if the air flow is out of specification, it means that the solenoid valve is occasionally stuck; if the air flow changes with the action of the solenoid valve, it means that the solenoid valve is normal.
The inspection results of the first three indicate that the inside of the solenoid valve has been worn out and must be replaced in the course of maintenance.
3. Thermal state inspection of solenoid valve
As the name implies, thermal inspection refers to simulating the set temperature that the automatic transmission can reach during normal operation, using a hot air blower or other oil, electric heating equipment, artificially heating the solenoid valve to its normal operating temperature, and then Carry out resistance and dynamic pressure test. If the check result is normal at this time, it means that there is no problem with the solenoid valve; if the performance is abnormal, it must be replaced without mercy.
