Volt

Park Engine On

When the transmission is operating in Park (Engine OFF), and the HPCM determines that vehicle operating conditions (low state of battery charge) are appropriate, the internal combustion engine (ICE) is started, the auxiliary fluid pump is turned OFF, and the main fluid pump provides hydraulic fluid pressure (refer to Engine Start ). After Engine Start, the following changes would occur to the transmission's hydraulic and electrical systems.

Pressure Control (PC) Solenoid 4

The PC solenoid 4 is commanded OFF, allowing PCS 4 signal fluid to exhaust from the 1-3 reverse clutch regulator valve.

Shift Solenoid 2

The shift solenoid 2 is commanded OFF, allowing solenoid 2 signal fluid to exhaust. When solenoid 2 signal fluid exhausts, the shift solenoid valve - mode A moves to the released position.

1-3 Reverse Clutch Assembly

13 reverse clutch fluid pressure is exhausted from the 1-3 reverse clutch housing assembly, allowing 1-3 reverse clutch spring force to move the 1-3 reverse clutch piston and release the 1-3 reverse clutch plates.

Shift Solenoid Valve - Mode A

13 reverse clutch fluid pressure exhausts at the shift solenoid valve - mode A.

#3 Ball Check Valve

13 reverse clutch feedback fluid pressure exhausts into the 13 reverse clutch/A cooling feed circuit, allowing actuator feed limit fluid to seat the ball.

1-3 Reverse Clutch Regulator Valve

1-3 reverse clutch regulator valve spring force moves the 1-3 reverse clutch regulator valve to the released position, allowing 13 reverse clutch/A cooling feed fluid pressure to exhaust.

Pressure Control (PC) Solenoid 5

The PC solenoid 5 is de-energised (OFF) allowing PCS 5 signal fluid to exhaust from the damper bypass clutch valve.

Torque Damper Clutch Assembly

Damper clutch fluid exhausts from the torque damper clutch assembly to the damper bypass clutch valve allowing the torque damper clutch to release.

Damper Bypass Clutch Valve

Damper bypass clutch valve spring force moves the damper bypass clutch valve to the released position, allowing damper clutch fluid pressure to exhaust through the valve into the exhaust backfill circuit.

Transmission Fluid Temperature (TFT) Sensor

Damper clutch fluid pressure in the exhaust backfill circuit exhausts at the TFT sensor.

1-3 Reverse Clutch Accumulator

13 reverse clutch fluid also exhausts from the 1-3 reverse clutch accumulator assembly. Accumulator spring force moves the 1-3 reverse clutch accumulator piston to the released position.