What are the causes of shift solenoid valve failure?
2 Answers
The main causes of shift solenoid valve failure are: malfunction of the main oil circuit pressure regulating valve, leading to excessively high main oil circuit pressure. The engine idle speed is too high. Below is a partial introduction regarding solenoid valve failure: Function: Change the transmission ratio; enable the vehicle to move in reverse while the engine rotation direction remains unchanged; utilize neutral gear to interrupt power transmission, allowing the engine to start, idle, and facilitating gear shifting or power output in the transmission. Working principle: A manual transmission mainly consists of gears and shafts, achieving speed and torque variation through different gear combinations; whereas an automatic transmission (AT) is composed of a torque converter, planetary gears, and a hydraulic control system, achieving speed and torque variation through hydraulic transmission and gear combinations.
I found that many car owners encounter shift solenoid valve failures primarily due to inadequate transmission fluid maintenance. Aged transmission fluid can produce sludge and metal debris, which can clog the solenoid's precise oil passages and cause valve core sticking. Another reason is the lifespan of electronic components—solenoid coils operating long-term in high-temperature environments are prone to open circuits or short circuits. Loose electrical connections are also a common factor, especially when transmission wiring harness interfaces accumulate dust or moisture, leading to poor contact. Additionally, sudden impact loads can easily cause failures, such as during aggressive driving with rapid acceleration and hard braking. Remember to change the transmission fluid every 60,000 kilometers, and don't wait until 200,000 kilometers for inspection—this can prevent over 80% of solenoid valve issues.
