What is a shift solenoid? What are the signs of a shift solenoid problem? How do you recognize a malfunctioning shift solenoid?
What is a Shift Solnoid?
Modern automatic transmissions are complex and have many components that work together to shift the vehicle’s gears. Automatic transmissions use hydraulic pressure to change the gears. The pressure of the transmission fluid can be controlled by electronic solenoids and gear shifting is possible. Shift solenoids is one such electronic solenoids.
The shift solenoids can be described as electro-hydraulic valves. It is part of a complex hydraulic system, which performs the exact same function as the clutch in vehicles with manual transmission. They control the transmission fluid flow. The engine control (PCM) and transmission control (TCM) gather various information from the vehicle speed sensors and engine. These parameters are used to calculate the time of the next gear change. It sends an electrical current to the solenoid circuit when it is time to shift gears. The solenoids can be opened or closed to control the flow of transmission fluid. The vehicle can be shifted by directing the pressured transmission fluid to various passages within the valve body.
Your automatic transmission’s valve body houses the transmission shift solenoids. These solenoids are built into the valve body, and you can access them on certain car models without having to remove the valve body.
What are the symptoms of Shift Solenoid Failure?
Shift solenoids can be exposed to fluids, metal chips, and high temperatures, which causes them to wear out. The solenoid eventually becomes inoperable and the transmission stops shifting properly.
A faulty shift solenoid can present with multiple symptoms that alarm the driver. These are the most common symptoms of a malfunction:
Irregular / Incorrect Shifting
An erratic pattern in gear changes is one of the first symptoms of a damaged shift solenoid. Each gear has one or two solenoids. One or more solenoids are required for each gear. If one fails, the transmission can’t shift into that particular gear but will instead shift to the next. The transmission might not be capable of shifting out of a particular gear if the shift solenoid is damaged while the gear remains engaged.
You may notice your vehicle shifting into another gear while driving at a steady speed. This can be dangerous and stressful. This happens when the solenoid switches on and off without receiving any signal from a transmission computer. It can also be caused by faulty wiring or short circuit problems. Unwanted gear shifts can happen in either direction. The transmission might downshift uncontrollably, which can cause RPM spikes. You may also notice the transmission shift to a higher gear. Your vehicle could stall because of this. Either way, it is important to diagnose the problem and fix it as soon as possible.
The exact cause of the malfunction may affect the severity of your symptoms. Sometimes, strange behavior may not occur while the vehicle accelerates. In other cases, however, problems may only occur when the vehicle slows down. This can be caused by a stuck solenoid, which is often a result of physical damage to the circuitry or is experiencing problems. The same problem can be caused by transmission fluid that is heavily soiled.
Delayed Shifting
Pressure is what makes automatic transmissions work. The transmission’s internal pressure changes are what make it shift gears. These pressure changes can only be achieved by the solenoids.
As solenoids age, they begin to experience a delay in changing gears. When shifting between gears while driving, you may feel “gaps”. You may feel like your car is losing its power at such times.
Both upshifting or downshifting can cause delayed shifting. Extended periods of downshifting can result in engine revs dropping if the transmission is left in a higher gear than it should be. It can also cause the engine to rev higher and overheat if the transmission stays in a low position for a prolonged time when it is supposed to shift. Delaying gear changes can lead to engine performance issues, increased fuel consumption, and damage to parts.
On
Check engine lights will come on when the shift solenoid fails. The check engine light will be illuminated if the PCM detects an issue with the shift solenoid circuit. The malfunction lamp’s illumination can also be caused by other causes. Therefore, it is important to check the fault codes in the PCM’s RAM and take the necessary repairs. P0700 is the most common fault code to indicate a transmission-related fault.
A transmission warning light is also available for some cars. The faulty solenoid may cause the light to turn on, or both.
Limp Mode (Failsafe Mode/Safe Mode)
Limp mode is a safety device that protects the vehicle’s engine, transmission and other components from damage in the case of a malfunction. The PCM restricts engine power according to the manufacturer’s program. It is not possible to increase engine speed beyond 2500-3000 rpm and transmission is limited only to 2nd or third gear.
