AUTOMATIC TRANSMISSION – ZF 5HP24 DESCRIPTION AND OPERATION Solenoid EPRS1 supplies a lower control pressure as the signal amperage increases. The EPRS1 solenoid is a normally closed regulating flow solenoid valve and regulates the mainline pressure. The solenoid is used for adaptive pressure control. The EAT ECU operates the solenoid using PWM signals. The EAT ECU monitors engine load and clutch slip and varies the solenoid duty cycle accordingly. Solenoids EPRS2, 3 and 5 supply a higher control pressure as the signal amperage increases. The solenoids are normally open solenoids regulating flow solenoid valves. The solenoids are used to regulate the supply of fluid pressure for clutch application during overlap up and downshifts of gears 2–3, 3–4 and 4–5. The EAT ECU operates the solenoids using a PWM earth proportional to the required increasing or decreasing clutch pressures. The resistance of the coil winding for solenoid EPRS1 is between 5.4 to 6.4 Ω at CF. The resistance of the coil windings for solenoids EPRS2, 3, 4 and 5 is between 5.9 and 6.9 Ω at C (68 ° F).