The causes of malfunctions may be purely mechanical, purely electrical, or both. There might occur over-shifting, incomplete shifting, or erratic shifting of speeds. When a control solenoid malfunctions, the primary effect is seen on the shifting quality. In every cycle, the signal is switched on for 50% of the time. Pulse-Width Modulated SolenoidДЄ pulse-width modulation is a signal that is switched on and off at a specific frequency for a specific amount of time.

The final position is defined as per the design requirements. When the coil is energized, the plunger moves to the other position by means of the magnetic force. On-off solenoids have defined plunger positions. Variable force solenoids can control the pressure in proportion (direct or inverse) to the input signal (in the form of current or voltage) from the controller. The plunger returns back to its normal position once the wire is de-energized. So, a normally open solenoid closes when the wire is energized, and vice-versa. When the wire is energized with flowing current, magnetic flux is generated, and the plunger is acted upon against the spring force. The solenoid may be normally open or normally closed. The solenoid consists of a spring-loaded plunger with a looped coil of wire wrapped around it. The seal material may be metallic or rubber, and must be chemically compatible with the transmission fluid. They ensure wear-free movement of the plunger, and provide leakage of transmission fluid (which is under pressure). Solenoid valve seals are located at the plunger end. It is wrapped around a spool-like frame that houses the plunger. The coil wire is generally copper or aluminum. In simple terms, solenoid coils convert electrical energy into mechanical energy (linear motion of the plunger). The solenoid coils get electric current supply through these wires. Lead wires are connected at the end of the solenoid. It is precisely machined for better linear movement, to provide accurate passage for transmission fluids Lead Wires The plunger is nothing but a bar made up of ferrous material. These solenoids are controlled electronically by micro-controllers, which process the information received from the various sensors located at different locations, and send appropriate signals. If the pressure is too high, the shifting is harsh, whereas, if it is too low, the clutch overheats. The shift quality is affected with the pressure applied by this fluid. This transmission fluid is responsible for generating the required pressure, and generates enough force to carry out these actions. Transmission control solenoids control the flow of transmission fluids into various compartments in the transmission unit, to carry out the engaging or disengaging of gear sets, clutches, and brake bands. What Does a Transmission Control Solenoid Do? Basic Structure of a Transmission Control Solenoid It directly affects the engine performance, as the load taken by it is dependent on the transmission module of the vehicle. A defective solenoid may cause problems like shifting into the wrong gear, or not shifting at all. The solenoid enables smooth shifting of gears to transmit appropriate speed and torque from the engine to the wheels. It is found in most modern-day vehicles, because of its accuracy and consistency in functioning. Transmission control solenoids are found in vehicles or transmission units with automatic or electrically controlled transmission systems for shifting speeds. If any of the two seem to be taking place, carry out a repair or replacement for the solenoid right away! Keep inspecting the valve body every once in a while (without dismantling any parts) for leakages and burning smells. This article explains the working and functioning of a modern-day transmission control solenoid. Failure in the solenoid directly affects the running of the vehicle. Most cars today use an automatic transmission system, which makes the вЂControl SolenoidвЂ™ one of the most important components in it.

Shift solenoid