Band Brake Solenoid

Band Brake Solenoid





A4S 310/270R: The band brake solenoid is used to regulate the flow of hydraulic oil to the band brake servo. The solenoid is normally open and allows full flow of hydraulic oil to the band brake servo to hold it engaged for 1st and 2nd gear. The solenoid is energized during application of the band brake to regulate the flow of hydraulic oil and soften engagement.

The solenoid is first energized with a a pulse width modulated signal from the TCM for approximately 2 seconds. It is then fully energized with a constant applied ground, to maintain a reduced flow.

The valve is then de-energized for full flow of hydraulic oil with the presence of road speed and an increase in engine load.

The band brake solenoid is energized by a shift from: N to D
D to N
3 to 2
4 to 2