LR3/Disco 3
Six Electronic Pressure Regulator Solenoids (EPRS) are located in the valve block. The solenoids are controlled by Pulse
width Modulation (PWM) signals from the TCM. The solenoids convert the electrical signals into hydraulic control pressure
proportional to the signal to actuate the spool valves for precise transmission operation.
The following table shows EPRS and their associated functions:
Solenoids EPRS 1, 3 and 6 supply a lower control pressure as the signal amperage increases and can be identified by a
black connector cap. The TCM operates the solenoids using PWM signals. The TCM monitors engine load and clutch slip
and varies the solenoid duty cycle accordingly. The solenoids have a 12V operating voltage and a pressure range of 0 -
4.6 bar (0 - 67 lbf.in
2
).
Solenoids EPRS 2, 4 and 5 supply a higher control pressure as the signal amperage increases and can be identified by a
green connector cap. The solenoids are normally open, regulating flow solenoid valves. The TCM operates the solenoids
using a PWM earth proportional to the required increasing or decreasing clutch pressures. The solenoids have a 12V
operating voltage and a pressure range of 4.6 - 0 bar (67 - 0 lbf.in
2
).
The resistance of the coil winding for the EPRS solenoids is 5.05 ohms at 20°C (68°F).
Control Solenoid
A shift control Solenoid Valve (SV) is located in the valve block. The solenoid is controlled by the TCM and converts
electrical signals into hydraulic control signals to control clutch application.
EPRS
Function
1
Clutch A
2
Clutch B
3
Clutch C
4
Brake clutches D and E
5
System pressure control
6
Torque converter lock-up control
