MECHATRONIC Valve Block
| ITEM | DESCRIPTION |
|---|---|
| 1 | Electronic Pressure Regulating Solenoid (EPRS) A - A brake valve |
| 2 | EPRS D - D clutch valve |
| 3 | EPRS B - B brake valve |
| 4 | EPRS E - E clutch valve |
| 5 | Magnetic Valve (MV) 2 - magnet-valve 2 for electrical park interlock (hold out of park) |
| 6 | MV 1 - pressure reducing valve |
| 7 | EPRS SYS - system pressure valve |
| 8 | EPRS WK - Torque converter lock-up clutch valve |
| 9 | EPRS C - C clutch valve |
| 10 | Transmission output shaft speed sensor |
| 11 | Hydraulic Impulse Storage (HIS) - if equipped |
| 12 | Electrical connector |
| 13 | Transmission Control Module (TCM) - hidden |
The mechatronic valve block is located in the bottom of the transmission and is covered by the fluid pan.
The mechatronic valve block houses the following components:
- The TCM
- Electrical actuators
- Speed sensors
- Control valves
- The Hydraulic Impulse Storage (HIS) (if equipped).
The above components provide all electro-hydraulic control for all transmission functions.
The mechatronic valve block comprises the following components:
- The TCM
- 7 Electronic Pressure Regulating Solenoids (EPRS)
- 2 park lock solenoids
- 21 hydraulic spool valves
- Temperature sensor
- Turbine speed sensor
- Output shaft speed sensor
- The HIS (if equipped).
Electronic Pressure Regulator Solenoids
The 7 Electronic Pressure Regulator Solenoids (EPRS) are located in the valve block. The solenoids are controlled by 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.
EPRS A, B, D, E and WK supply a higher control pressure as the signal amperage increases and can be identified by an orange 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 - 4.7 bar (0 - 68 psi).
EPRS C and SYS supply a lower control pressure as the signal amperage increases and can be identified by a gray connector cap. 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 4.7 - 0 bar (68 - 0 psi).
The resistance of the solenoid coil winding for EPRS is 5.05 Ω at 20°C (68°F).
Control Solenoid (MV 1)
A shift control solenoid Magnetic Valve 1 (MV1) 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.
The shift control solenoid is an open/closed, on/off solenoid which is controlled by the TCM connecting the solenoid to ground. The TCM also supplies power to the solenoid. The TCM energizes the solenoid in a programed sequence for clutch application for gear ratio changes and shift control.
The resistance of the solenoid coil winding for solenoid is between 10 to 11 Ω at 20°C (68°F).
Control Solenoid (MV 2)
| ITEM | DESCRIPTION |
|---|---|
| A | Solenoid in locked (energized) condition - park lock released |
| B | Solenoid in unlocked (de-energized) condition - park lock engaged |
| 1 | Solenoid |
| 2 | Claw - locked |
| 3 | Piston |
| 4 | Claw - unlocked |
A control solenoid Magnetic Valve 2 (MV 2) is located in the valve block. The solenoid is controlled by the TCM and converts electrical signals into hydraulic control signals to control the electronic park lock function.
The control solenoid is an on/off solenoid which is controlled by the TCM by connecting the solenoid to ground.
When the park position is deselected, control solenoid MV2 resets the parking lock valve in the mechatronic valve block. This is achieved by the TCM providing the ground for the solenoid which is energized, releasing the claws from retaining the park lock piston. Main ATF pressure acting on the parking lock piston, pushes the piston back to release the lock.
When the park position is selected, control solenoid MV2 is de-energized. The ATF pressure at the parking lock cylinder piston is vented and the mechanical interlock of the piston is opened. A pre-tensioned torsion spring at the park lock disc pulls the piston into the 'park' position. In the 'park' position the piston engages with the control solenoid claws and is locked in the park position. An emergency release wire cable can be used to release the parking lock manually if an electrical failure occurs.
The resistance of the solenoid coil winding for solenoid is 25 Ohms at 20 °C (68 °F).
When the neutral "N" position is selected and the engine is turned off, the ATF pressure at the park lock cylinder piston is released. The current supply to the control solenoid MV2 remains. The park lock cylinder piston is still held in the unlocked position by the spring force acting on the park lock disc. This prevents the park lock plate from engaging the parking lock. This allows the vehicle to be moved when the engine is not running for a short time. Should the battery voltage fall below the level required to maintain the solenoid in the energized condition, the park lock is engaged.
Sensors
Speed Sensors
The turbine speed sensor and the output shaft speed sensor are Hall effect type sensors located in the mechatronic valve block and are not serviceable items. The TCM monitors the signals from each sensor to determine the input (turbine) speed and the output shaft speed.
The turbine speed is monitored by the TCM to calculate the slip of the torque converter clutch and internal clutch slip. This signal allows the TCM to accurately control the slip timing during shifts and adjust clutch application or release pressure for overlap shift control.
The output shaft speed is monitored by the TCM and compared to engine speed signals received on the FlexRay system bus from the PCM . Using a comparison of the 2 signals the TCM calculates the transmission slip ratio for plausibility and maintains adaptive pressure control.
Temperature Sensor
The temperature sensor is also located in the mechatronic valve block. The TCM uses the temperature sensor signals to determine the temperature of the ATF . These signals are used by the TCM to control the transmission operation. The TCM uses the temperature signals to promote faster warm-up in cold conditions. The TCM also uses the temperature signal to assist with ATF cooling by controlling the transmission operation when high ATF temperatures are experienced. If the sensor fails, the TCM uses a default value and a Diagnostic Trouble Code(s) (DTC) is stored in the TCM .
Spool Valves
The valve block contains spool valves which control various functions of the transmission. The spool valves are of conventional design and are operated by ATF pressure.
Each spool valve is located in its spool bore and held in a default (unpressurized) position by a spring. The spool bore has a number of ports which allow ATF to flow to other valves and clutches to enable transmission operation. Each spool has a piston which is waisted to allow ATF to be diverted into the applicable ports when the valve is operated.
When ATF pressure moves a spool, 1 or more ports in the spool bore are covered or uncovered. ATF is prevented from flowing or is allowed to flow around the applicable waisted area of the spool and into another uncovered port. The ATF is either passed through galleries to actuate another spool, operate a clutch or is returned to the fluid pan.